Steel Buildings in Europe

Part 3: Actions 3 - 31 8.3 Flowcharts Fundamental value of the basic wind velocity v b,0 Construction location National map Directional factor c dir Season factor c season Basic wind velocity v b Terrain category Roughness factor c r ( z ) Peak velocity pressure q p ( z ) Orography factor c o ( z ) Basic velocity pressure q b Air density  Terrain factor k r Turbulence factor k l EN 1991-1-4 § 4.2(1) (See National Annex) EN 1991-1-4 § 4.5(1) EN 1991-1-4 § 4.3.2 EN 1991-1-4 § 4.3.3 and A.3 (See National Annex) EN 1991-1-4 § 4.4 (See National Annex) Reference height z EN 1991-1-4 § 4.5(1) Figure 8.6 Flowchart A: calculation of the peak velocity pressure Type of surface External pressure coefficients c pe on vertical walls Wind forces F w,e and F w,i Peak velocity pressure q p ( z ) Friction coefficient c fr Reference area A fr External pressure coefficients c pe on roof Internal pressure coefficients c pi See Flowchart A EN 1991-1-4 § 5.3 EN 1991-1-4 § 7.2.9 EN 1991-1-4 § 7.5 Table 7.10 EN 1991-1-4 § 7 Structural factor c s c d EN 1991-1-4 § 6 and Annexes B, C, D (See National Annex) Friction forces F fr EN 1991-1-4 § 5.3 Dimensions of the building Figure 8.7 Flowchart B: Calculation of the wind forces