Impact load from falling snow and ice 1

[cbinder]

I am in need of information to determine design criteria for some canopies that I am designing. Existing structure is a 50' tall metal building used to melt down and recycle aluminum. Last year, sliding snow and ice fell the 50' and totaled a workers truck. The sliding occurred at the location where the furnaces are, which makes complete sense. I found the info regarding what the sliding snow load is, but I haven't found much regarding ice damming as well as impact from those falling onto a lower roof.

Thank you in advance for any assistance!

 

[r13]

I suggest to provide thermal protection/device to the upper roof, and divert the melting ice water somewhere else.

 

[JAE]

Probably a very difficult thing to "codefy" as the variables would be immense.

Here's one short article - there are many others online but nothing too specific to your question:

http://www.unm.edu/~bgreen/ME360/Impact Loads.pdf

 

[RPMG]

Ice damming is when water freezes at the eaves and causes water to flow backwards underneath shingles/flashing.

I believe you're looking for roof snow rails and guards.

 

[phamENG]

Implementing products like what RPMG shows is a good place to start.

If you still need to design for impact, look at ASCE 7 for approximate snow densities. From there, you can determine a mass of falling snow and calculate its kinetic energy when it reaches the canopy. So long as your canopy can absorb that much energy in the elastic range, you should be ok. Determine an appropriate factor of safety and fine tune the analysis. Assuming a non-deformable body for the snow would be incredibly conservative, but determining the deformation of your snow ball would probably be an exercise in futility.

 

[human909]

but determining the deformation of your snow ball would probably be an exercise in futility

Or a hell of alot of fun with your kids!

 

[bones206]

Good safety topic to keep in mind this time of year... particularly in Russia! Youtube video