Ground Snow equivalent depth?

[leeStruct]

Need help here Please.

I have got a question on Snow load which puzzled me a long time.

In ASCE7-05, equation (7-3) gives the density of the snow:

Garma=0.13pg+14 but not more than 30pcf

according to this equation, one can calculate the equivalent depth of the snow covered on ground by divide the pg with above calculated Garma value, say if in a 40psf ground snow zone, the equivalent ground snow depth will be 40/(0.13*40+14)=2.08 ft. Is that conception correct?

Thanks.

 

[woodman88]

Equation 7-3 is for snow drift density not ground snow. The ground snow can be more dense, but the snow that get blown off the ground to creat drifts is assumed to meet this equation.

Garth Dreger PE
AZ Phoenix area

 

[leeStruct]

Is that ground snow value means a statistics for a whole year's snow accumulation, not just one snow fall?

Thanks.

 

[RockEngineer]

A lot of the density of snow depends on where you are also. Cascade sludge on the western coast Washington, Oregon and California can get water content so high it almost approaches the density of water. That's how we get ground snow loads between 250 psf and 600 psf. Dry fluffy snow like they get in most of the rocky mountains is much lighter.

 

[msquared48]

Yea.

Just wait till you have to design a wood roof to 400 psf and you are frantically trying to save the owner some money.



Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask