I have witnessed two completely opposite methodologies when it comes to resolving the static forces acting in a timberframe through the braces. An engineer tells me that I should treat the braces as if they were posts; Essentially that a beam that joins a brace below can be divided into two separate beams; one beam between the post and brace, and one beam between the brace and the far end of the beam.

At first this made sense, but after I thought about it I realized that if this were true, braces would almost always be carrying huge loads and would be some of the largest timbers in a timber frame, and inspection tells me that this is not the case.

Fast forward to last night. I was checking out a book on "timber engineering". Primarily a book on designing glulams and metal connectors, etc., but with a brief section on "traditional joinery". Their text stated that they considered braces strictly as members for resisting lateral loads -- wind, seismic, etc. When they worked their calculations for beam sizing, joint shear etc, they sized the beams as if the braces weren't even there. They concluded that since beam shrinkage would likely increase the distance that braces would need to span, and the braces would stay the same length, considering the braces for weight bearing was dubious.

This made much more sense to me. Although, I think that the truth lies somewhere between both methods.

Anyone with more experience want to chime in?