IRC Portal Frame Question

[XR250]

Does anyone know if this is the capacity for both connectors combined or for each?

 

[phamENG]

I've always assumed that it's each. Scroll up to Figure R602.10.6.2 and it seems to say that the hold down capacity is an 'each' value and I believe the "Portal Frame for Engineered Applications" paper clarifies it as such.

 

[XR250]

Fair enough. A Simpson LPT4 does not have enough capacity in SPF. Would you consider adding some vertical timber screws to supplement?

 

[phamENG]

Fair enough. A Simpson LPT4 does not have enough capacity in SPF. Would you consider adding some vertical timber screws to supplement?

I'd be hesitant to do that. Can you require longer fasteners to make up the difference?

 

[XR250]

Longer fasteners in the LPT4? What is you hesitation with timber screws to supplement? Honestly, I have a pretty wide wall segment on this one so I can use 4 clips but for argument's sake and future jobs I'd like to hear what you have to say.

 

[jerseyshore]

Fair enough. A Simpson LPT4 does not have enough capacity in SPF. Would you consider adding some vertical timber screws to supplement?

I like how the footnotes say that an LTP4 satisfies the IRC requirements even though it clearly does not.

 

[SE2607]

...satisfies the IRC requirements even though it clearly does not.

This is the issue I have with the IRC in general. A LOT of things don't calc out, or at least didn't when I last looked at it. At the time, I came to the conclusion that the IRC was for simple structures far away from high seismic and wind zones. But, that is a different thread. Sorry for the hijack in advance.

 

[phamENG]

Longer fasteners in the LPT4? What is you hesitation with timber screws to supplement? Honestly, I have a pretty wide wall segment on this one so I can use 4 clips but for argument's sake and future jobs I'd like to hear what you have to say.

Mixing fastener types. Load sharing between different fastener types or configurations is pretty tough to predict, and is not always directly additive. So I avoid it where I can.

Yeah, the longer fasteners don't really work, do they? Not at a rim board. Might be worth using a length of coil strap?

LPT4 works for Southern Pine for the prescriptive code. They should probably expand on that a bit in the footnote, though.

 

[XR250]

Mixing fastener types. Load sharing between different fastener types or configurations is pretty tough to predict, and is not always directly additive. So I avoid it where I can.

Yeah, the longer fasteners don't really work, do they? Not at a rim board. Might be worth using a length of coil strap?

LPT4 works for Southern Pine for the prescriptive code. They should probably expand on that a bit in the footnote, though.

Meh, it's residential. Every aspect of it falls in the "unpredictable load sharing realm"

 

[phamENG]

Enjoy your ride, cowboy. I'll hang back here at the camp.

I was thinking about it this morning (because I'm a nerd and have nothing better to think about, apparently), and I bet it does work, even with SPF. The purpose of the plate is to pass the shear and uplift from the sheathing above the joint to the sheathing below, as it's already passed out of the studs. So the primary concern will be the nailing of the plate to the sheathing, with the penetration into the studs serving to improve the connection behavior over a simple 1/2" embedment. If we assume that the sheathing to stud nailing is sufficient to have them act together, it becomes a question of the nail behavior through the two layers of "main member". The important part of the connection will likely have a G = 0.5, giving a better connection value. It would likely be less than the listed value for SP in the Simpson table, but I'm guessing it would be higher than the SPF value. One of those gray areas that live between the discrete engineering world and the prescriptive world...

Best bet, if you're going to use prescriptive values, is to reach out to Simpson and ask about that footnote. I'd be surprised if they haven't knocked over a few of these built from SPF to make sure they perform the way the IRC intends.

 

[XR250]

LOL.

So OSB has a G of 0.5? I never figured that.

 

[phamENG]

From APA Panel Design Specification: