Atmospheric Icing Load on Bar Grating
Atmospheric Icing Load on Bar Grating
(OP)
How do you compute the ice load on bar grating? The bars are too closely spaced to use the ice load from one bar and take summations. It's not exactly a flat horizontal plate. And why does ASCE equation 10.4-2 have pi as a factor for ice volume on large flat plates?
Mapped Ice Th. = 3/4"
Design Ice Th. = 1 1/2"
Grating: 1 1/2"x1/8" 19W4
Or do you not bother with ASCE, and assume that there is a 3" sheet of ice?
Thanks!
Mapped Ice Th. = 3/4"
Design Ice Th. = 1 1/2"
Grating: 1 1/2"x1/8" 19W4
Or do you not bother with ASCE, and assume that there is a 3" sheet of ice?
Thanks!






RE: Atmospheric Icing Load on Bar Grating
Dave
Thaidavid
RE: Atmospheric Icing Load on Bar Grating
Does anyone understand why, for a large flat horizontal plate, the volume of ice is: Vi = pi * td * As (ASCE 7-10 10.4-2)? I'm pretty sure that if I measured it with a tape measure, I wouldn't multiply the volume by pi.
RE: Atmospheric Icing Load on Bar Grating
So, a single "flat platform" around a tower would have to be larger than that:
( [(Tower_dia + 2 x platform radius) x pi - (Tower_dia x pi) ] x the ASCE_Factor ) x )nbr of platforms)
Then you'd have to add the intermediate stairs or ladder areas.
RE: Atmospheric Icing Load on Bar Grating
RE: Atmospheric Icing Load on Bar Grating
(Of course, note that when considering combined ice and wind, ASCE 7 (figure 10-2) as well as NESC allow for reduced wind loads)
RE: Atmospheric Icing Load on Bar Grating
njiutzwe: I was looking at load combination 2 for ASD (D + L + Di), which includes live load. However, I agree that if there is 3" ice, there is no live load. I believe that this is within the code's intent. The platforms may be subject to "roof (environmental)" or "floor" loading conditions, but not at the same time.
Lomarandll: I have not forgotten about wind. Ice wind is about 1/8 of the normal wind force in this case.
Thanks everyone
RE: Atmospheric Icing Load on Bar Grating
www.SlideRuleEra.net
www.VacuumTubeEra.net