Gable end wall to diaphram shear xfer

[tricalcim]

Given: Conventional light weight wood construction with premanufactured trusses, shear walls, and platform framing, non-blocked diapram.
My understanding of the load path to the roof diaphragm (for wind load parallel to ridge) is via the gabled end truss connection top (sloping) chord. On some plans I see diagonal bracing (at say 4'oc) running at 45 degrees form the level top plate of the end wall and connecting back into diaphram.
Q: pls let me know is my understanding is right and help me to understand the need, or requirments, for the bracing. Either UBC or I - code referencing's are fine too.

As alway, appreciate any discussions and your time.

 

[UcfSE]

You have to have a continuous member (balloon framing) or some sort of connection between the gable-end truss and the top plate to provide continuity across that joint. Otherwise you have a hinge in the middle of your wall. Since making the connection act continuous is not feasible, bracing is used to brace that part of the framing.

 

[Redfish205]

Have you been to this website?

http://www.sbcindustry.com/structuremagazine.php

I have a copy of BCSI 1-03 and have found it extremely helpful. You can download for free or have a hard copy, which I like, for $8.00 and it isn't one of those flimsy books either. Each page is laminated.

 

[tricalcim]

thanks - I feel that now I have, at least, a couple of options. I bookmarked the web-site, it did have a similiar topic of discussion.

When I use a brace it seems I can either design it so that I can xfer the loads into the roof diaphram via the brace (platform framed), or balloon frame and use the top chord of the truss for load transfer. I suspect, in some instances, I be using a combination of the two options.

thx.............