Snow Load on Double Gable or Sawtooth?

[brownieboy]

Hey,

First, could someone please point me to a thread if this has already been discussed.

I'm wondering what snow loads you might use in this case. (See snip). The roof is existing and must be replaced as-is. I looked at a sawtooth unbalanced snow load. My senior engineer said drifts won't control. Also, I considered sliding snow, but there isn't really an eave at the valley. I'm happy to provide any additional details you might find necessary.



BTW: I don't have control over member layout/orientations. Only upsizing if necessary. So any framing changes/recommendations aren't going to do anything. lol

Thanks!

 

[alt0]

I would consider using 1.3-1.5x flat roof SL at the flat roof zone. I don't think this is codified anywhere but is often used in my region.

 

[jerseyshore]

At the normal high/ low location (left side of sketch), I'd check drift vs sliding snow to see what's worse.

At the cutout in the middle, I would just use a lot of snow load, even if checks for sliding/ drift don't require much more. That's just a judgement spot where you know snow can pile up bad. Maybe double it. Or use a 12'x3.2' area and superimpose that over the smaller 3.5' length. Just make it a lot.

 

[EngDM]

At the normal high/ low location (left side of sketch), I'd check drift vs sliding snow to see what's worse.

At the cutout in the middle, I would just use a lot of snow load, even if checks for sliding/ drift don't require much more. That's just a judgement spot where you know snow can pile up bad. Maybe double it. Or use a 12'x3.2' area and superimpose that over the smaller 3.5' length. Just make it a lot.

I had a similar situation a couple months back, and my route was just to make it a heavy snow load.

 

[brownieboy]

Thanks all!