Snow and Live Loading Combinations of an Occupied Roof Deck 1

[Fisherman77]

I am looking for some type of documentation to help support (or argue against) this statement:

"IBC 2015 load combinations including .5L + 1.6S, and 1.6L + .5S, were not considered in the design of the roof deck. Because the assembly area is outdoors, an extreme snow load (1.6S) will result in the area being uninhabitable. Additionally, a moderate snow load (.5S) will prevent a dense crowd of people (1.6L) from congregating outside. For this reason, combinations including roof live loads predominately govern."

 

[msquared48]

The first condition says that fewer people will be on the deck with more snow, and that the snow is likely to be piled up in certain areas of the deck so that some people can congregate.

The second condition says that more people will be on the deck with less snow - Uniform snow condition unshoveled.

That's my take, but as for reality? Who knows? Use the EWAG principle...

Personally, I think it's a snow job.

Mike McCann, PE, SE (WA)

 

[MotorCity]

Be careful...... live load is NOT the same as roof live load. In the load combinations, you are only required to account for rain OR snow OR roof live load. The "L" used in the equations above is not for the roof, for the simple logic you state above. You will not have people gathering on a roof while standing knee deep in snow.

 

[JAE]

For an occupied roof deck, though, there is L loading....not just Lr.



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