Civil Engineering Reference
In-Depth Information
Figure G8-4
Plan view of
monoslope roof for
Example 8-2.
Since this drift height is greater than the clear height,
h
c
, the drift width,
w
, is
larger than 4
h
d
. Using the “equating the areas” relation from Section 7.7.1,
the drift width is
4
h
d
2
/
h
c
=
4(3.3 ft)
2
/2.8 ft
w
=
=
15.6 ft
Yet from the “aerodynamically streamlined drift” relation, the drift width
cannot exceed
w
≤
8
h
c
=
8(2.8 ft)
=
22.4 ft
In this case, the “equating the area” relation controls, and the total maxi-
mum load (balanced plus drift) is
4.0 ft(18 lb/ft
3
)
72 lb/ft
2
p
max
=
h
RTU
×γ=
=
The resulting load at the RTU is sketched in
Figure G8-5
.
Example 8-3
Parapet Wall Drift,
Low Ground Snow Load
Problem
Solve the same problem as Example 8-1, except that
p
g
is 15 lb/ft
2
.
