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# Eurocode 1 Wind load on prismatic elements with rectangular cross-section (force coefficient)

Description:
Calculation of wind load action effects on prismatic elements with rectangular cross-section. The total horizontal wind force is calculated from the force coefficient corresponding to the overall effect of the wind action on the structure
According to:
EN 1991-1-4:2005+A1:2010 Section 7.6
Applicable for:
Structures with rectangular plan, isolated elements with rectangular cross-section
Supported National Annexes:
Α) Calculation of force coefficients: Apart from countries that adopt CEN recommended values for sections 7.6 and 7.13 of EN1991-1-4, the following National Annexes are supported: Croatia. B) Peak velocity pressure: The value of the peak velocity pressure can be specified manually. Otherwise automatic calculation of peak velocity pressure is supported, in addition to countries that adopt the CEN recommended values for NDPs, also for the following National Annexes: Finland, Portugal. The National Annexes of Germany, Norway, Spain, Sweden, Switzerland are NOT supported (enter peak velocity pressure manually).
Input

Hint: Select 'Custom peak velocity pressure' in the terrain category dropdown in order to manually specify the peak velocity pressure.

The terrain categories are illustrated in EN1991-1-4 Annex A. The transition zones between terrain categories are specified in EN1991-1-4 §A.2. For a description of the terrain categories 0, I, II, III, IV see Calculation of peak velocity pressure.
m/s
The basic wind velocity is given as vb = vb,0cdircseason where the fundamental value of basic wind velocity vb,0 is defined in EN1991-1-4 §4.2(1)P and its value is provided in the National Annex. Altitude correction may also be specified in the National Annex for EN1991-1-4 §4.2(2)P. The directional and season factors are generally cdir = 1.0 and cseason = 1.0. For particular cases values smaller than 1.0 may be specified in the National Annex for EN1991-1-4 §4.2(2)P.
kPa
m
m
m
For cross-sections with sharp corners r=0
m
m

Orography factor larger than 1.0 may be applicable over isolated hills and escarpments. See EN1991-1-4 §4.3.3 and §A.3 for more details.
Structural factor cscd in accordance with EN1991-1-4 Section 6. A value of cscd = 1.0 is generally conservative for small structures not-susceptible to wind turbulence effects such as buildings with height less than 15 m.
Nationally Defined Parameters
kg/m3
According to EN1991-1-4 §4.5(1) and the National Annex.
According to the National Annex to EN1991-1-4 §4.1(1), §4.2(1)P, §4.2(2)P, §4.3.1(1), §4.3.2(1), §4.3.5(1), §4.4(1), §4.5(1).
According to the National Annex to EN1991-1-4 §7.13(2).
Note: Always verify the validity of the Nationally Defined Parameters (NDPs). Please inform us of any discrepancy using our Contact Form. The NDP value is left blank for all NDPs that we do not have this information available. Interested users who have access to the corresponding NDPs can notify us using our Contact Form to fill-in the missing information.