Wind Loads on Main Wind Force Resisting System and Components & Cladding


According to EN 1991-1-4 [1] Wind actions on structures and structural elements shall be determined taking account of both external and internal wind pressures. The external pressure coefficients cpe for buildings and parts of buildings depend on the size of the loaded area A, which is the area of the structure, that produces the wind action in the section to be calculated.

The external pressure coefficients are given for loaded areas A of 1 m2 and 10m2 in Tables 7.1 to 7.5 for the appropriate building configurations as Cpe,1, for local coefficients, and Cpe,10, for overall coefficients, respectively. The recommended procedure for loaded areas up to 10 m2 is given in figure below.


According to the figure above, when the size of a loaded area is higher that 10 m2, the cpe,10 is being used. However, the loaded area tributary to components and cladding (e.g. Purlin) may be less than 10 m², therefore, an additional set of wind pressures is calculated and considered for components and cladding, using the appropriate cpe.



Reference:

[1] EN 1991-1-4 (2005) (English): Eurocode 1: Actions on structures - Part 1-4: General actions - Wind actions https://www.phd.eng.br/wp-content/uploads/2015/12/en.1991.1.4.2005.pdf