I have been doing timber frame structural engineering design for
10-15 years and have run into a
problem with a building department that I have never encountered before.
This building official is saying that we can not use a timber frame as the primary
lateral load resisting Structural System because it is not defined in the
1997 Uniform Building Code, Table 16-N. This is a plan checking service for
El Dorado County Building Department here in California. They are saying I
can use the timber frame system as long as I provide plywood shear walls or
otherwise (SIP's) designed system. I'm just curious if any of you have run into that
anywhere before. Any ideas on how I can argue against this wacko
interpretation?

We have done many timber frames in Nevada, Washoe and Placer counties and always use the exterior enclosure system as the lateral load resisting system. We use the frame only for gravity and uplift resistance

It is my understanding from taking a course from Dick Schmidt and Rob MacKay and working with other structural engineers, that the timber frame does not have rigid enough joinery to be considered a moment frame, nor enough bracing to be considered a braced frame.

There is an article in the new Timberframing magazine about larteral resistance. I haven't read it yey, but it might address your concerns.

I'd love to hear others opinions.

HTH
Kurt