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Interior Bearing Wall

Interior Bearing Wall

Interior Bearing Wall

(OP)
I have a gable roof, using metal plated wood trusses that bear on three 6" walls.  Two of the walls are exterior, and the third is interior.  My spans will make the truss manufacturer use three trusses per line.  One piggyback to make the peak, and two across the spans.

My question is, at the interior bearing wall will the truss manufacturer butt the trusses or will he lap them?  The 6" (5.5") wall surely wont allow for the butted condition will it?  I dont have access to the TPI code.

RE: Interior Bearing Wall

If the span is great enough to need 2 trusses, there is a decent chance that 2.75" of bearing won't be enough. But, that could be solved with bearing blocks.  IT would be best for sheathing the roof if all 3 trusses could be in the same plane.

Bracing of the lower trusses at the interior bearing is another issue.

RE: Interior Bearing Wall

Loui1,
Depending on the geometry of the roof planes, the truss designer could design the system such that you have full bearing and still have them in line.  One of the trusses would have to be a "top chord bearing" truss.  This truss would bear on a top plate that ran across a shortend end vertical of the other trusses.  
 

RE: Interior Bearing Wall

KEEP the trusses in line. All too often truss designers simply instruct you to lap trusses at interior bearings with no thought to the increased roof-ply application cost both in materials and labor.

Calculate the actual and required bearing needed.
Actual: 2x6 plate=> 5.5"/2=2.75"
Required for DF/SYP: MaxGravityReaction/625/1.5"width= ??

A side scab to the bottom chords over the interior bearing will distribute the reaction load even more. For higher loads and smaller bearings, the trusses can stack atop each other and/or vertical scabs can be added at the butt splice.

Too often the truss designer eliminates an oversize bearing requirement by extending a vertical web through to the bearing (Fc parallel to grain values instead of perpendicular). Unless the bearing support is steel, the problem has simply moved to crushing of the wood wall top-plate.

RE: Interior Bearing Wall

Has anyone given consideration to what the truss manufacturer could actually put on a truck?

RE: Interior Bearing Wall

60 foot max length

RE: Interior Bearing Wall

Seriously, how large are your spans and what slopes are you looking for?  Assuming that the total span is greater than 60' will your standard 2x6 bearing walls handle the applied truss loadings.  Once you get to trusses of this size the truss technician/manufacturer should take a step back and call on a structural engineer to evaluate the whole system.

RE: Interior Bearing Wall

(OP)
Sorry man, I'm asking about the details of how they butt trusses together.....Not about spanning 60' up in the mountains with a serious snow load or something.

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