@MTF,
I am not certain if there are any studies on this. I saw some studies done on pegs but not tenons.
I am trying to visualize what will happen if a load is applied to a bend with three posts and four braces. Most frames are joint very tightly so the load would put immediate compression on two off the braces and would do nothing to the other two braces. And if the joinery due to shrinkage or poor craftmanship has some "play" the braces if pegged should be able to resist some tension if the tenons were made long enough. A short tenon will not be able to resist the amount of tension that a longer tenon would. I think that the thickness of the tenon and the wood species would matter also. It takes more force to shear off a 3" thick tenon rather than a 11/2" tenon.
Also if the braces were actually made longer the would probably do a better job 'bracing' the frame. Yet most frames only see 36" braces but have 8'-10' posts.
@ Gabel,
that depends on what you consider a traditional frame. Are you refering to traditional frames globally or just in the US?
I do agree though that any frame wether simple with little bracing/small braces or true stand alone does benefit from siding or roof sheathing nailed to it. If you have a frame with infill and want the frame to rely on it than in all likelyhood the infill would start falling out rather sooner than later because of the frame wrecking and breaking the infill.
Once the frame is closed in the problem wether there is tension on the braces or not is minimized to almost nill anyway. I do not believe that it is such a big concern after all. Otherwise we would not see frames that are hundreds of years old, because then they should have failed after just a few storms.
