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Re: Ridge beam/joist analysis

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And that's why we often become unglued (un-nailed)?  :^)
Thor A. Tandy P.Eng
Victoria BC
email: vicpeng(--nospam--at)
----- Original Message -----
Sent: July 1, 2004 10:03 AM
Subject: RE: Ridge beam/joist analysis

I have a terminology comment that might help to clear up this discussion.

In the wood design that I'm familiar with doing, "collar ties" refer only to
a 2x horizontal member that is nailed to the upper 1/3rd of a pair of
sloping rafters. The purpose of the "collar tie" is only for a construction
aid and/or to help prevent separation of the rafter tops during wind uplift
(suction) events. As has been noted previously, they are negligibly
effective in restraining the rafters against spreading at the top plate.

"Rafter ties" are a separate bit of framing that are nailed to the bottom
(or at least below the bottom 1/2) of the rafters.  In typical framing,
these members would also act as the ceiling joists.  Only the "rafter tie"
connection would be designed for the tension created by the lateral
spreading force at the base of the rafters.  Two separate terms for two
separate functions...

Eli Grassley
PSM Engineers
Seattle, WA