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Pitched Tapered Glu-Lam in a three pinned Arch

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Well, I had a little problem dropped on my desk about a week ago, and I've been picking the brains of glu-lam fabricators as well as a few people at AITC, and no one has been able to an answer that I or the engineer I work under is willing to accept, so I'll throw it out to the list.  And I'll do my best to avoid referencing any of the good Clinton jokes I've heard this week.
We're designing an addition and a couple of new buildings that match and existing church.  The new structures will have TS columns at the perimiter, and pitched and tapered glu-lams for the main spans, about 40 foot spans with an eight foot overhang.  Two glu-lams will make up a three pinned arch, and we'll have some type of tie bar across the middle so we're not bending the cantilever columns (at least not with gravity loads).  My problem is that, unlike examples from AITC, the radius of the beams are on the top - ie, in compression - and the tapered face will be in tension due to bending.  This is exactly the opposite of most textbook examples.  There is also the additional bending and compression due to the arch, and the question of where is the best elevation along the beams to tie the too together (at the top of the columns, at midspan, etc.).
If any of you timber gurus out there could point me toward a design reference that handles more complex design of glu-lams like this, I would appreciate it.
Thanks in advance
Paul McEntee
Biggs Cardosa & Associates
San Jose, California
Can a throw in a funny anecdote from work today?
We're retrofitting this bridge, and the basic scheme is to infill the space between columns with these monstrous concrete walls.  We were going over what calcs needed to be done according to Caltrans specs, and one of them was to show that the walls & footing won't overturn.  So a co-worker of mine says something along the lines of:  "It's ridiculous that we have to show that these walls aren't going anywhere.  I mean, it would take an act of GOD to make this thing overturn."
Senior engineer on the project looks at him and says "Yeah, it's a good thing we're not designing for an earthquake or anything like that."