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RE: RESIDENTIAL: Discussion of Load Paths

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Good comments, however...
 
Note the quote below:
 
"...many time[s] two hips oppose each other and a ridge frames in at the same point you could resolve the forces into a self supporting system up to a critical load which would be much lower than the critical load if you put a support at the end of the hip or valley. But again the diaph has very little to do with this."
 
Meaning ABSOLUTELY no disrespect--because these are the kinds of comments that I get from "all sources"--but this is difficult for me to understand. It sounds like more of those "residential roofs aren't amenable to the laws of statics" comments that I seem to hear from many.
 
The two hips don't actually "oppose each other" because they are BEAMS framing into a common point--unlike rafters, for example. If you have two hip beams with a slope of, say between 30 and 45 degrees, coming together at a "point", that common point isn't held up by a sky-hook! It has to be supported somehow, UNLESS you can show that the diaphragm action of the sheathing keeps them in place. These are NOT "out of plane" forces I'm talking about, they are IN-PLANE forces of the sheathing that is NOT in the plane that is defined by the two hips (I hope that's clear; personally I always have a problem with verbal descriptions of geometry).
 
If so, fine. If not, well, as someone else here said, there are some engineers that insist on columns or struts at those locations.