Lateral Load from Snow Drifted at a parapet
Lateral Load from Snow Drifted at a parapet
(OP)
I am working on a job where there are narrow cavities created at the roof between a parapet and a higher tower-like structure. The snow drift in this cavity is around 70 psf. I did not do the design, but am working with a specialty material supplier. The design calls for VERY large members in the wall of the tower at this location. I thought the design is just overly conservative as the lateral capacity of this wall is in excess of 200 psf.
I asked the engineer's representative why this was so and they said it was because of the snow drift. Having worked with a lot of snow, I never considered that piled snow imparted a significant lateral load onto a wall.
Does anyone know of any studies or reports of lateral loading resulting from drifted snow?
I asked the engineer's representative why this was so and they said it was because of the snow drift. Having worked with a lot of snow, I never considered that piled snow imparted a significant lateral load onto a wall.
Does anyone know of any studies or reports of lateral loading resulting from drifted snow?






RE: Lateral Load from Snow Drifted at a parapet
RE: Lateral Load from Snow Drifted at a parapet
I know the structure is over-designed, It just got me curious about lateral loading from snow drift.
RE: Lateral Load from Snow Drifted at a parapet
RE: Lateral Load from Snow Drifted at a parapet
Come to think of it, all the ski resorts and pictures I have seen of huge snow drifts and now structural failures because of lateral loading. I think on a microscopic level snow flakes must interlock as they pile up on each other, they do not behave like a frictionless soil against a retaining wall.
RE: Lateral Load from Snow Drifted at a parapet
RE: Lateral Load from Snow Drifted at a parapet
Mike McCann
MMC Engineering
RE: Lateral Load from Snow Drifted at a parapet
RE: Lateral Load from Snow Drifted at a parapet
RE: Lateral Load from Snow Drifted at a parapet
I don't think it would hurt to provide for some lateral pressure, but the amount cited in this thread seems a bit excessive.
BA
RE: Lateral Load from Snow Drifted at a parapet
BA, I agree that there must be some load, but I'm a little surprised at the apparently complete lack of guidance in the literature.
One would think if the affects were minimal, that the codes would at least claim this if no rational procedure existed for finding the load.
Patrick
RE: Lateral Load from Snow Drifted at a parapet
Could the design engineer have been considering this load to be an impact load from the snow shedding off a high roof?
Personally I don't ever recall seeing a drift leaning on a structure. (NE Ohio Lake effect)
I always though (hypothesized) that as the snow fell a little wind would swirl at the wall and hold the drift back somehow.
RE: Lateral Load from Snow Drifted at a parapet
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BA
RE: Lateral Load from Snow Drifted at a parapet
I think this would be a case where a "V" shaped sawtooth roof would create a wedge of snow (sloping roof driving snow into a vertical clerestory window) that would develop some kind of lateral load.
But on a vertical parapet, with no wedge-shaped snow load from an adjacent sloped roof, there just wouldn't be any lateral force developed in my opinion.