Snow Load (due to Drift) - Upper limit

[Eng-Tareq]

Hello All,

For Canada, is there an upper limit on how much load you can use for snow drift load? In other words, if the Snowdrift load from neighboring roofs was calculated to be 10 kPa would you design for the 10 kPa roof load or use a certain set maximum by the NBC? If so what is that maximum?

 

[BAretired]

I have never heard of an upper limit for snow load. Just follow the code.

 

[jayrod12]

The code puts upper limits on it by telling you to take the lesser of the calculated Ca values where appropriate. There are no further exceptions that I'm aware of.

 

[CDLD]

Without looking into it, I believe the drift height is limited to the obstruction height.

 

[EngDM]

There is no upper limit, however at a certain roof step height the drift begins to decrease (using 2020 NBCC).

 

[DaveAtkins]

The only other exception I know of is with canopies. Snow drift is limited to a 30 degree angle of repose. Before the code had this exception, when you had an industrial building with a long upper roof and a small canopy at a doorway, you got ridiculous snow buildup on the canopy. I am talking about ASCE 7.

DaveAtkins