Civil Engineering Reference
In-Depth Information
Figure 8.20
Mean pressure distributions on
multi-span buildings and comparison with a
single span (Holmes, 1990b).
8.6
Effects of parapets on low-rise buildings
A detailed wind-tunnel study of the wind effects of parapets on the roofs of low-rise
buildings was carried out by Kopp
et al.
(2005a, b). Earlier work was reviewed by
Stathopoulos and Baskaran (1988).
It was found that tall parapets, (
h
p
/(h
+
h
p
)
>0.2), where
h
p
is the parapet height, can
reduce peak local negative pressures by up to 50% in corner regions of a roof, when they
are installed around the complete perimeter of a roof. Lower parapets, (
h
p
/(h
+
h
p
)
<0.2),
increase the worst negative peak pressure coefficients, apparently by stabilizing the
corner conical vortices that occur on flat or near-flat roofs (see Figure 8.8). However,
high parapets increase the positive (downwards) pressure peaks on the roof upwind of
leeward parapets.
