Connecting Hurricane Ties...with Powder Actuated Fasteners?

[phamENG]

Question for everyone. I have a case where I need to connect a hurricane tie to the side of a steel tube. Welding is not desirable due to access issues and surrounding wood framing, and there's no room to add a nailer AND account for cross grain fun.

So I was thinking...is there an issue with using PAFs to attach Simpson hangers to steel? So long as they are the correct diameter, the hanger shouldn't care, and as long as they have the appropriate shear and pullout capacities the connection should be good. I suppose there's some risk of damaging thinner connectors in the process? Anyone have any thoughts or concerns about it? I'll reach out to Simpson, but figured I'd float the idea here first.

I looked at screws, but none of them take screws large enough to drive into this steel.

 

[milkshakelake]

I use PAFs on 18 GA thin cold formed steel all the time, and Simpson hurricane ties tend to be that gage, so they should be okay to withstand the impact. My concerns:

1. Simpson hurricane ties tend to use 0.131" to 0.148" diameter connectors. PAFs are usually 0.157" diameter. Something to think about. Maybe use a smaller PAF than usual.
2. Connectors that have a bump out (like TSP) - I'd be worried about crushing the bump out. There's a difference in force between a nail gun and a PAF gun. For the same reason, I'd shoot the PAFs first before shooting the nails; very minor thing though, shouldn't make a real difference.

Also, in case the access issues make it hard to install a Simpson connector, you could always use a generic cold formed steel angle, like L3x3x18 GA. Kind of lets you play around with edge distance, spacing, and getting easy access.

 

[phamENG]

Thanks. Simpson has one PAF that comes close to matching diameter, but it's not quite right. Worst case I'll just do basic checks on the base material. I'll see what options Simpson gives.

 

[milkshakelake]

If you're doing some checks on the material itself, edge distance starts becoming a concern with something bigger than the recommended nail diameter. PAF can punch through and widen the hole diameter. I'm sure there's a little bit of leeway in the hole diameter, like with steel, but that's already been accounted for with the smaller diameter fasteners.

 

[WesternJeb]

The simpson hurricane straps typically include a safety factor of 3. Punching a hole that is .01" (6%) in diameter larger than the intended hole diameter seems pretty inconsequential to me compared to that safety factor. That is how my senior engineers and myself have justified using the PAF for the hurricane straps and other simpson connectors when needed.

 

[BridgeSmith]

Assuming the steel is thin enough (and flat enough) for the PAF pin to penetrate, I would think the pullout capacity would be very low.

 

[milkshakelake]

If it's 0.01" larger than intended, then yeah, I don't see any issue.

 

[phamENG]

BridgeSmith - these are loaded in shear. Pullout isn't a concern.

 

[Celt83]

Worth reaching out to Simpson directly on this one, they have a lot of their connectors dual rated for wood and CFMF so would expect they get asked about PAF's enough since they are so common in the CFMF world. Also to the extent that they offer any warranty they do have this void clause:

 

[phamENG]

Thanks, Celt. That was my thought, too, so I pulled out my CFMF connector catalog and was suprised they don't have any direct to steel fasteners for this sort of arrangement. It seems common enough in that world to have trusses or CFS joists sitting directly on a structural steel beam.

That's great, though. Oh, you used common nails that we didn't manufacture? Too bad! Warranty voided...