Advanced Package Training Scaffolding 2011.1 - Scia-Software GbR

Annex A: Wind pressure versus Wind force
85
Scaffolding
In paragraph “6. Load cases” the wind has been calculated with EN1991-1-4 and calculated as a wind
pressure.
Following EN 12810-1, it is also possible to calculate the wind as a wind force using the following
formula (EN 12810-1, (1)):
= ∙ ∙ ∙
With
Ai is the reference area specified in EN 12810-1, Table 4 (see also below)
cf is the aerodynamic force coefficient taken from EN 12810-1, Table 5 (see also below)
cs is the site coefficient taken from EN 12810-1, Table 6 (see also below)
qi is the design velocity pressure in accordance with EN 12810-1, Figure 3:
In this example, the height of the structure is 11m, so qi on 11m is + 940 N/m² and on 0m + 800 N/m².
When inserting one value a average of those two can be taken: 870 N/m².
The reference Area Ai:
Cladding condition of the
system configuration
Reference area Ai
Unclad Area of each component projected in the wind direction
Clad Surface area of the cladding (see A.3 of En 12811-1:2003)
This example was an unclad example. For a component with a diameter of 48,3mm, the area is
0,0483m x Lcomponent.
The aerodynamic force coefficient cf :
Cladding condition of the
system configuration
Force coefficient
Normal to the façade Parallel to the façade
Unclad 1,3 1,3
Clad 1,3 0,1