Buttressed Arch. Question for Ron N.

[Ron Nossaman]

> I don't KNOW, Ron. But if you keep talking I'll shut up and listen. If my
> brain were as flexible as Sitka, I'd be fine.
> Thanks,
> Fenton


When you bend a piece of wood (rib), the fibers on the convex 
outside of the bend are stretched, and the fibers on the 
concave inside of the bend are compressed. So if you glue an 
expanding panel on one side of that piece of wood (rib), it 
will stretch the rib's fibers at the glue joint as it expands, 
bending the rib. Bending the rib stretches the fibers on the 
outside of the curve (top), and stretching the fibers on the 
top face of the rib causes the rib to bend and increase crown. 
It's that simple, and has not a thing to do with an arch. The 
panel will still rise and fall with humidity swings because 
the compression level in the panel changes with it's moisture 
content, and the resulting degree to which it stretches the 
top side of the rib changes with it, changing the crown rise 
as a result. Still no arch involved, it's a self contained 
leverage that works without end buttresses.

Better?
Ron N