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Glulam arch (Was: Re: Seismic load path)

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Gerard Madden wrote:
> 
> Use a tudor or reverse curb glulam three-hinged arches for the gravity
> system and for stability in the transverse direction.
> 
> See the timber construction manual, 4th edition, for further info.
> 
> Gerard Madden, P.E.
> Civil Engineer, Associate
> CRJ Associates, Inc.


I have used glulam arches for this purpose before, but ran into the
problem that there is no R factor for them in the Standard Building Code
(no Rw factor in the UBC either, I believe). The code has some language
about other structural systems besides those listed can be used if
analytical and test data are submitted that establish the dynamic
characteristics  and energy dissipation capacity to be equivalent to
some other listed system, then you can use the same R as for that
system.

As far as I could determine after talking to the engineering department
of a glulam manufacturer, the American Institute of Timber Construction,
and several other engineers, no one knows of any such "analytical or
test data" for glulam arches. I did get a lot of guesses, usually "well,
we think it's about the same as an ordinary steel moment frame".  

I know from reading the messages here,that many of you work in areas
where your design work receives serious review by plan checkers, code
officials, etc.  So in areas such as these:

1. Are glulam arches just never used for a lateral load resisting
system?
2. Do the reviewers accept a guess such as "Rw same as ordinary steel
moment frame".
3. Or is there some published data that is out there that answers this
question.

Thanks,
Rick Burch, PE
Johnson & King Engineers
Columbia, SC