Simpson Strong-Tie Hanger Wood Species Question

[Zoobie777]

Hi,

When selecting hangers does the wood species for factored resistance apply to just what the hanger is attached to or does it include what is hung? For example, if I have a D.Fir girder and I want to hang an SPF truss on it, do I used the factored resistance for D.Fir or SPF?

Thanks in advance.

 

[XR250]

Since the weak point is usually the connection to the girder, then I would use the DF.

 

[Zoobie777]

I guess I should clarify. In the Simpson catalogue a certain hanger has a factored resistance rating for D.Fir of 1500 lbs. The same hanger is rated for 1200 lbs. for SPF. My SPF truss load on the hanger attached to a D.Fir girder is 1300 lbs. Is this hanger suitable?

Thanks

 

[skeletron]

Check out the Simpson connector selector design tool for manufacturer non-catalogue recommendations

https://www.strongtie.com/softwareandwebapplications/category

From a quick run of the tool, it looks like the uplift is affected by the species of the supported (SPF) member. The supporting (DFIR) member seems to govern the main loading, though. Which is probably how I would expect to size it.

Joist --> bearing on seat --> hanger nails --> nails bearing on header wood

 

[Zoobie777]

Wow. I didn’t know Simpson had software for this. Will be sure to check this out in the morning. My colleagues will love this.

 

[Zoobie777]

Good to note about the uplift. That’s exactly what I’m dealing with. Architect has designed 5’ overhangs with Canadian snow loads.

 

[skeletron]

If in doubt, go conservative (SPF). Wood is shite these days and a hanger is relatively inexpensive.

 

[skeletron]

Also, I've seen 5' OH up here and it actually looks insane. Truss guy needed a "structural fascia" detail when it was rebuilt.