Hi Mark,
To clarify the structure, three bents - two eave and one ridge. The spacing between bents is 10'-0". There are three 14 foot bays on each bent adding to the 42'-0".
As I said, history shows knee braces work, or at least don't seem to suffer catastrophic failures. Roof covering and pitch have a lot to do with the loads seen. I'm dealing with a shingled roof. Shingled roofs don't shed snow. Metal roofs readily shed snow. Not knowing what kind of roof you have, I couldn't even comment.
I believe that in reality some load does go to stiffness, but as Jordan stated, the codes establish design criteria which minimizes the likelihood of failure in the interest of both life and property protection. The building codes generally establish loads based on a 2% probably model of the load ever being exceeded. The NDS establishes wood design properties based on the percentage of members whose strength falls below the design strength. Thus, it is reasonable that structures which don't necessarily pass a design check still do not fail. But when a PE starts accepting designs that don't meet established design criteria, it's a slippery slope if one wants to keep their license. I know I do.
Thanks for your reply.
