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Re: Story Drift: 1994 UBC vs. 1997 UBC

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Bill-
en/2 is for dry lumber. on the west coast it's nothing but green lumber so
use 1.2en. I'd also suggest bumping up your da to account for oversizes
holes, sill compression, and construction slop (simpson's test values are
for steel test jigs, not wood posts).
chuck utzman

Bill Allen wrote:

> See revised calculations at:
>
> http://www.allendesigns.com/SW/ShearWallDeflections.htm
>
> Still, Dm > 0.025 * h (slightly, but this is a fairly low stressed shear
> wall)
>
> Regards,
>
> Bill Allen, S.E.
> ALLEN DESIGNS
> Laguna Niguel, CA
>
> > -----Original Message-----
> > From: Seaintonln(--nospam--at)aol.com [mailto:Seaintonln(--nospam--at)aol.com]
> > Sent: Thursday, August 12, 1999 8:36 PM
> > To: seaint(--nospam--at)seaint.org
> > Subject: Re: Story Drift: 1994 UBC vs. 1997 UBC
> >
> >
> > Bill,
> > I reviewed your calc's on your website and have the following
> > comments:
> >
> > 1. When I created this model in Excel I found that the units
> > of the terms do
> > not balance. The first term, for example, 8fvh^3/EAb is not
> > intended to be
> > converted to comparable units as Mathcad would do
> > automatically. This is one
> > of those examples that I wrote about in the Mathcad / Excel Thread.
> > I received a number of responses to my previous threads as to
> > how the units
> > balanced and one or two list members sent me a complete
> > breakdown as to how
> > to the Algebra from 5wl^4/384EI converted to this formula
> > above. The problem
> > was that Mathcad converted the units which inflated the
> > results - the results
> > should be in the following units:
> > fv = psi
> > h = ft
> > E = psi
> > A = in^2
> > b = ft
> > The inclination is to convert feet to inches and, in this
> > case, would inflate
> > the answer by a factor of 12.
> >
> > The next issues is the Load per nail that you use. This
> > should be the actual
> > nail load based on the actual shear in the panel rather than
> > the allowable
> > capacity of the plywood - therefore, your load per nail
> > should be somewhat
> > less. This is moot since you might be assuming that your
> > demand is equal to
> > your capacity in this example.
> >
> > I might be wrong on this one, but the t for a non-structural
> > grade 3/8" thk
> > panel should be 0.298" rather than 0.373. I did not take the
> > time to check my
> > spreadsheet, but this is what I get off the lookup tables.
> > Again, I might be
> > the one who is wrong here.
> >
> > The nail elongation term is another one where the units are
> > not suppose to
> > balance. the results are to be in inch-feet but assumed
> > inches. Again, this
> > is an emperical formula and nobody to date has been able to
> > tell me why
> > constants of 1/feet was not used to clarify this. This might
> > yield an error
> > of 12 times in Mathcad.
> >
> > If you are interested in the translation from the normal simple span
> > deflection formula to the first term of this deflection formula (the
> > deflection in the chords) I can provide it to you.
> >
> > Let me know if I have made this clear - I think others are
> > making the same
> > mistakes.
> >
> > Dennis
> >
> >
>