Steel Buildings in Europe

Title Appendix A Worked Example: Wind action on a multi-storey building 2 of 18 3 - 23 2. Peak velocity pressure 2.1. General For a multi-storey building, the peak velocity pressure generally depends on the wind direction because the height of the building is higher than the width of the upwind face. Therefore we have to distinguish between:  Wind on the long side  Wind on the gable The calculation of the peak velocity pressure is performed according to the detailed procedure described in Section 7.2.1 of Single-storey steel buildings. Part 3: Actions [10] . 2.2. Wind on the long side 1 Fundamental value of the basic wind velocity v b,0 = 26 m/s 2 Basic wind velocity v b = c dir c season v b,0 EN 1991-1-4 § 4.2(2) For c dir and c season , the recommended values are: c dir = 1,0 c season = 1,0 Then: v b = v b,0 = 26 m/s 3 Basic velocity pressure 2 b b 2 1 v q   where:  = 1,25 kg/m 3 EN 1991-1-4 § 4.5(1) Then: q b = 0,5 × 1,25 × 26 2 = 422,5 N/m 2 4 Terrain factor k r = 0,19 ( z 0 / z 0,II ) 0,07 The terrain category is III. Then: z 0 = 0,3 m (and z min = 5 m) z 0,II = 0,05 m Then: k r = 0,19 × (0,3 / 0,05) 0,07 = 0,215 EN 1991-1-4 § 4.3.2(1) 5 Roughness factor c r ( z ) = k r ln( z / z 0 ) for: z min ≤ z ≤ z max c r ( z ) = c r ( z min ) for: z ≤ z min EN 1991-1-4 § 4.3.2