Steel Buildings in Europe

Title Appendix A Worked Example: Wind action on a multi-storey building 3 of 18 3 - 24 where: z max = 200 m z is the reference height The total height of the building is: h = 35 m The width of the wall is: b = 120 m h ≤ b therefore q p ( z ) = q p ( z e ) with: z e = h = 35 m Therefore c r ( z ) = 0,215 × ln(35/0,3) = 1,023 EN 1991-1-4 Figure 7.4 6 Orography factor Since the slope of the terrain is lower than 3°, the recommended value is used: c o ( z ) = 1,0 EN 1991-1-4 § 4.3.3 7 Turbulence factor The recommended value is used: k l = 1,0 EN 1991-1-4 § 4.4(1) 8 Peak velocity pressure q p ( z ) = [1 + 7 I v ( z )] × 0,5  v m 2 ( z ) EN 1991-1-4 § 4.5(1) where:  = 1,25 kg/m 3 (recommended value) v m ( z ) is the mean wind velocity at height z above the terrain v m ( z ) = c r ( z ) c o ( z ) v b = 1,023 × 1,0 × 26 = 26,6 m/s I v ( z ) is the turbulence intensity I v ( z ) = k l / [ c 0 ( z ) ln( z / z 0 ) ] for: z min ≤ z ≤ z max I v ( z ) = I v ( z min ) for: z ≤ z min Then: I v ( z ) = 1,0 / [1,0 × ln(35/0,3)] = 0,21 q p ( z ) = [1 + 7 × 0,21] × 0,5 × 1,25 × 26,6 2 × 10 -3 = 1,09 kN/m 2 2.3. Wind on the gable Several parameters are identical to the case of wind on the long side, as follows: 1 Fundamental value of the basic wind velocity v b,0 = 26 m/s 2 Basic wind velocity v b = 26 m/s EN 1991-1-4 § 4.2(2)