Lateral snow load
Lateral snow load
(OP)
I need to design 5 feet tall parapet in area of ground snow load equal to 90 psf. Snow drift is more than 5 feet. How can I find lateral snow load on parapet? Any ideas?
Thanks.
Thanks.
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
Download nowINTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
|
RE: Lateral snow load
RE: Lateral snow load
RE: Lateral snow load
RE: Lateral snow load
RE: Lateral snow load
You could perhaps calculate the snow density and treat it like a fluid (no internal shear strength) and see what kind of lateral load this theoretical fluid imposes. This is not a code requirement that I know of and is probably pretty conservative. Namely, if the roof parapet can withstand the wind that deposits a leeward drift, then it can probably take the indeterminate lateral load of the snow too.
The only lateral snow loads (that I know of) that the code says to consider is per ASCE 7.9. At the higher elevations here in Colorado, alot of the local building departments specify snow guards to prevent a big chunk of snow or ice from sliding off a metal roof and hitting a person below, typically over ingress/egress doors. These lateral forces can be quite large.
RE: Lateral snow load
Thanks guys, I was hopping someone knew internal friction angle of snow, to reduce fluid pressure. Thanks.
RE: Lateral snow load
RE: Lateral snow load
This implies some sort of internal friction (phi) angle for snow. The internal friction angle is probably quite high (nearly 90 degrees) with any thaw freeze cycling. Would this be analagous to cohesion?
Anyway, you could use some sort of phi angle to calculate an "at rest" lateral coefficient using a unit weight of about 20 pcf.
You could add this lateral fluid pressure due to the windward (not leeward) drift at the parapet to the wind suction. I have never done this, and the code does not prescribe this, but there are instances when there might be some sort of fluid bin pressure due to loose snow, I think.