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Diaphragm Chord Wood Roof

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I have a design and detail question.  I’m working on a single story wood framed building with truss rafter roof.  The lateral stability for wind is provided by wood sheathed shear walls.  The trusses are parallel chord with bottom chord bearing.  There is also a tall parapet that is part of the truss.  At the face of wall the vertical member of the truss extends up to form the parapet.

 

On previous typical truss rafter roofs using gable type trusses I design the top plate of the wall to be the chords of the diaphragm.  I put in blocking between the trusses and transfer the shear down into the top plate of the wall. 

 

On this project I’m wondering what is the best way to detail this so that the force comes out of the diaphragm and into the top plate of the wall, if that is possible.  If this is not practical, where else can I put the chord?  The end of the truss is 32” deep. The plywood sheathing will extend up to the top of parapet.   I thought about trying to run a ribbon at the sheathing level, but since I have this extension up for the parapet that does not seem feasible.

 

Anyone come across this problem before and have some creative solutions for designing and detailing the chords of the diaphragm?

 

Thanks for your help.

 

Rich