Civil Engineering Reference
In-Depth Information
density in lb/ft
3
versus snowpack depth in inches as predicted by the Equa-
tion 7-3. Due to an upper limit of 30 lb/ft
3
, the density is constant for depths
greater than 49 in. or ground loads greater than 123 lb/ft
2
. At shallower snow
depths, the formula yields roughly a 1 lb/ft
3
increase in density for every 3 in.
or so of additional depth.
Figure G7-8
is a plot of snow load (lb/ft
2
) versus snow depth (in.). It
includes a density relation from Tabler (1994) for snow before the onset of
melt. Notice that these two independently developed unit weight relations
provide remarkably similar snow loads for snow depths less than 4 ft. Also,
both curves (ASCE 7-10 and Tabler) are convex (i.e., the density or unit weight
is an increasing function of depth). This increase is due, at least in part, to
self-compaction due to the weight of the overburden snow.
The Tobiasson and Greatorex (1996) relation between 50-year load and
50-year depth from
Equation G2-1
and
Figure G2-1
is shown as a dashed
LIVE GRAPH
Click here to view
Figure G7-8
Snow load vs. snow
depth.
