> You have a beam that is ( theoretically )  x long, y wide &
> z thick.  Weight is applied perpendicular to the xz plane.
> Beam is supported at both ends of the length.  What happens
> if you compare it to a beam of the same material x long, 2y
> wide and z thick ?

As I recall, weight capacity is essentially based on length
(x) and thickness (z).  As Z increases, resistance to bending
stress goes way up (non-linear).  While strength is only
directly related to width (y) -- i.e. a linear factor.

Besides the high-tech, on-line sources, the US Department of
Agriculture has some excellent publications, available through
the US Government Printing Office (GPO), on wood framing and
basic structural strength.  They're aimed not at the structural
engineer but the farmer who needs to construct a building that
isn't going to collapse while in use.

> For example: If you have a beam made of 7/16 inch OSB that is
> 21 feet long and 8 inches wide.
> How much stronger will a similar beam be if it is 16 inches wide ?

I think it's a simple factor of 2 stronger.  OSB (Oriented
Strand Board) may not follow the rules of a solid wood beam
due to it being chunks of wood glued together (non-linearity
at joints where adjacent pieces meet).

						Lee Jones

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