BWW:
I have come up against the same results, and this is my approach and rationalisation: I have never seen a brace buckle or a post snap where a brace pushes on it. In cases where I have examined leaning barns, the only failure observed at compression braces is crushing of the bearing surfaces of the brace housing. Before I model a frame, I draw up a typical brace end connection and calculate the allowable force in the brace based on bearing areas of the joint as discussed in TFJ&DWB. (This has always been less than the allowable axial strength of the brace per NDS.) I then model the frame with braces as compression only members. My first pass always comes up with brace forces too high. I then reduce the cross sectional area of the brace members and repeat until the model brace forces are less than the joint can handle. When I need a tension brace to make things work, I let a steel rod into the top edge of the brace and run it through the post and beam.
Happy modeling,
Chris
