2008/10/1 Carl Denk <cdenk@alltel.net>

> Actually OSB is fairly homogenous, and is used in large scale, where the
> defects are accounted for in the allowable stresses. Plywood has
> different allowable loading parallel and perpendicular to the grain of
> the face ply. And all these formulas apply only in the linear zone and
> less than the elastic limit (after deformation, the piece returns to
> it's original shape when the load is removed), and all safe loading is
> in this area.
>
> I can't caution enough, as a registered structural engineer though, 85%
> of structural failures are details, connections, etc. , NOT the main
> member (beam or column). Think Holiday Inn Kansas City where a small
> connection killed and severely injured many; The I-35 bridge in
> Minneapolis where a plate failed, and this isn't just big structures.
> Compared to the entire structure, the cost of a competent engineer is
> inexpensive, and may save money by recommending more economical material.
>

If this is building code NBC/CBC/local relevant there are tables for "silent
joists" and paralams(sic?) etc. Deflections usually limited to 1/360 of the
length IIRC.
Anything not in table usually requires a stamp, even substituting two 2x10s
with douglas fir 6x12...
D
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