Rafter hanger nail collision at ridge beam

[StrEng007]

This is a bit of an odd question.

I've got rafters that will be face mounted to a supporting ridge beam. I'm using engineered wood for the ridge beam, which has allowed a reduction in the overall width of the member.

The hanger hardware I'm looking to specify uses 16d nails. I'm concerted about the nails colliding when rafters are installed each side. I don't want to have to offset one side.

What's the solution for this?

 

[jayrod12]

I've never actually seen this be an issue in practice.
Do you need full hanger capacity? If not, there's often reduction factors that can account for using shorter nails. Or screws.

 

[dvd]

Not sure what product you are using but my Simpson LRU series use a short nail or screw and the attachment points are offset on the sides of the rafter to avoid this problem.

 

[StrEng007]

Oh, that LRUZ is going to be perfect. Thank you!

 

[XR250]

You could put a ledger on the bottom of the LVL in lieu of hangers.

 

[ChorasDen]

You could put a ledger on the bottom of the LVL in lieu of hangers

And here we are back into the issue of cross grain tension. I don't recommend a ledger below the neutral axis.

 

[lexpatrie]

Granted, but there is (now) at least testing for a ledger connection.

See the FAQ under wood construction. The prescriptive ledger connection appears to be so weak that cross grain tension is not the failure mode.

That was meant for floor construction but it's probably directly applicable minus the slope of the rafter if that has any effect. Unless you connect the ledger "too much" and change the failure mode to cross grain tension.

 

[XR250]

And here we are back into the issue of cross grain tension. I don't recommend a ledger below the neutral axis.

90% of the houses I review use ledger strips for the floor system. I have never seen a cross grain failure - just the ledgers peeling off when the joists are loaded excessively (from a offset load bearing wall condition for example).

 

[ChorasDen]

How do you achieve target reliability for such a loading condition like cross grain tension when codified design values are not provided? I would not suggest nor endorse a loading scenario that induces tension perp personally, but I suppose I cannot prevent you from doing so.

 

[XR250]

Well ledgers for floor joists are in the building code