Advanced Package Training Scaffolding 2011.1 - Scia-Software GbR

IV Area in which at least 15% of the surface is covered with buildings
and their average height exceeds 15m
18
Advanced Training
1,0 10
For Belgium, vb,0 equals 26.2m/s following the EC-EN. In addition Cdir and Cseason are all equal to 1.
From this vb can be calculated (EN 1991-1-4 (4.1)):
C ⋅ C ⋅ v
vb = dir season b,
0
= 26,2m/s
In terrain class III the mean velocity vm are calculated using the following formula (EN 1991-1-4
(4.3)):
where
c ( z)
⋅ c ( z)
⋅ v
vm = r o b
co(z) is the orography factor taken as 1,0 (unless specified otherwise in EN 1991-1-4 §4.3.3.)
and
cr(z) is the roughness factor given by formula (EN 1991-1-4 (4.4)):
⎛ z
cr ( z)
= kr
⋅ ln ⎜
⎝ z0
cr r
And
( z)
= c z
k
r
( )
min
⎛ z
= 0,
19⎜
⎜
⎝ z
⎞
⎟
⎠
0
0,
II
⎞
⎟
⎠
0,
07
For
for
z ≤ z ≤ z
min
(EN 1991-1-4 (4.5))
z ≤ zmin
The evaluations of these formulas for this example and category III gives:
k
r
⎛ z
= 0,
19⎜
⎜
⎝ z0,
( z)
= k
cr r
0
II
⎛
⋅ ln
⎜
⎝
⎞
⎟
⎠
0,
07
z
z
And the mean velocity:
m
0
⎛
= 0,
19⎜
⎝
0,
3
0,
05
⎞
⎟
⎠
0,
07
=
⎞ ⎛ 11 ⎞
⎟ = 0,
215 ⋅ ln⎜
⎟ =
⎠ ⎝ 0,
3⎠
0,
215
0,
776
v m/s
= cr
( z)
⋅ co
( z)
⋅ vb
= 0,
776⋅1
⋅ 26,
2 = 20,
3
Out of these values the peak velocity pressure is calculated by:
max