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Re: Lumber Moment Frame Connection

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This has been a great thread (even though, it drifted a little far from patio covers)

To refocus on the Jim's question & follow up on Scott's comment

IF one used values out of the NDS  AND used a R=1

would (should?)  this engineered solution (custom 3/16" L strap both sides) pass plan check?

Plus is Jim's solution better or worse than the "plan check acceptable" knee braces?

IMO, if properly designed, its got be a lot better than knee braces.

cheers
Bob

On 3/2/07, Lloyd Pack <packman90(--nospam--at)qwest.net> wrote:
On 1 Mar 2007 at 16:08, Jordan Truesdell, PE wrote:

> If the calculations were performed per the NDS and AISC spec and all
> show positive margins of safety using rational engineering analysis
> what grounds does the plan checker have - other than their gut feel -
> to deny the permit? What magic is occurring in the moment connection
> which does not result in tension, compression, and shear forces of a
> known quantity? Given the dimensional change and deterioration of
> lumber in the natural environment, why is it that bending moment,
> shear, and defined fastener-steel-wood interactions are allowed for
> nearly every other case? Is the lumber somehow aware that there is a
> moment connection at the free end? Does a post embedded 3' into
> concrete or soil figure there's no use in failing because there's a
> special formula in chapter 18 that allows such a use?

This last sentence was funny.  And I agree with your position here.


> I don't necessarily mean to take the discussion in this direction, but
> have we, as engineers, fully given up engineering as a science in
> favor of checking off boxes and filling numbers into equations in a
> book?
> Jordan

This seems to be happening more and more, the checking of boxes.
The codes give us some guidance and a base from which to look at things,
but the can also limit creative thinking and solution finding.  When we
go to the fundamentals and break the problems down, we can sometimes
come up with innovative solutions that haven't been thought of and
therefore haven't been codified, yet.

It would be easier to have more faith in the codes as being a tome of
collective wisdom of our profession, if it weren't so politically manipulated.
There are too many non-engineers having significant imput and control
over the outcome of the codes to not take them with a grain of skepticism,
and ask the questions of how this came to be in the code and why should
I perpetuate its existence?

Take care,
Lloyd Pack

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