Steel Buildings in Europe

Title APPENDIX B. Worked Example: Wind action on a single-storey building 2 of 11 3 - 47 3. Basic velocity pressure 2 b 2 1 b v q   where:  = 1,25 kg/m 3 (recommended value) Then: q b = 0,5  1,25  26 2 = 422,5 N/m 2 EN 1991-1-4 § 4.5(1) 4. Terrain factor 0,07 0, II 0 r 0,19          z z k EN 1991-1-4 § 4.3.2(1) Table 4.1 The terrain category is category III, then: z 0 = 0,3 m z min = 5 m 0,215 0,05 0,19 0,30 0,07 r         k 5. Roughness factor        0 r r ( ) ln z z c z k z is taken equal to the height of the building: z = 8 m Then: 0,706 0,3 ( ) 0,215 ln 8,0 r          c z EN 1991-1-4 § 4.3.2(1) 6. Orography factor The building is erected on a suburban terrain where the average slope of the upwind terrain is very low (< 3°), so: c o ( z ) = 1 EN 1991-1-4 § 4.3.3(2) 7. Turbulence factor The recommended value is used: k l = 1,0 EN 1991-1-4 § 4.4(1)