Calculation No. COMPANY NAME CALCULATION NO. CALCULATION SHEET Project No. PROJECT NUMBER onlinestructuraldesign.com Project Title: Project Name Calc. By Author Subject/Feature: Wind reference pressure calculation - Eurocode 1 (EN 1991-1-4) Checked By Checker qp (z) = ce (z) * qb Air density ρ= 1.25 kg/m3 season factor vb = cdir * cseason * vb,0 = Basic velocity pressure 2 qb = 1/2 * ρ * vb = Terrain category: => 30 m/sec 562.5 N/m III 0.3 5 z0 = zmin = 2 kr = 0.19*(z0/z0,II) 0.07 = Terrain orography: co (z) = 1 Wind turbulence kl = 1 Date per EN 1991-1-4 Section 4.2 Note 2 - Reccomended value is 1.0 Other values may be specified by the National Annex per EN 1991-1-4 Section 4.2 Note 3 - Reccomended value is 1.0 Other values may be specified by the National Annex per EN 1991-1-4 Section 4.2 (1)P Expression (4.1) per EN 1991-1-4 - Section 4.5 (1) Expression (4.10) per EN 1991-1-4 - Table 4.1 roughness lengths m ; m Terrain roughness: cr(z) = kr * ln(z/z0) for zmin < z < zmax cr(z) = c r(zmin) for z < zmin z0,II = 0.05 zmax = 200 0 Date Value specified in the National Annex Basic wind velocity calculation cdir = 1 directional factor 1 Rev. per EN 1991-1-4 Section 4.5 (1) Expression (4.8) The National Annex may give other rules for the determination of qp(z). per EN 1991-1-4 Section 4.5 Note 2 - Reccomended value is 1.25 Other values may be specified by the National Annex Fundamental value of the basic wind velocity vb,0 = 30 m/sec cseason = Date Date per EN 1991-1-4 Section 4.3.2 per EN 1991-1-4 Section 4.3.2 (1) Expression (4.4) m per EN 1991-1-4 Section 4.3.2 Expression (4.5) - roughness length for terrain cat. II m per EN 1991-1-4 Section 4.3.2 Expression (4.5) - max. roughness length to be taken as 200m 0.2154 per EN 1991-1-4 Section 4.3.2 Expression (4.5) terrain factor depending on z 0 per EN 1991-1-4 Section 4.3.1 Note 1 for flat terrain co (z) = 1.0 for other types of terrain see section 4.3.3 & Annex A.3 - turbulence factor; lv(z) = k l /(c0(z)*ln(z/z 0)) for zmin < z < zmax per EN 1991-1-4 Section 4.4 (1) recommended value is 1.0, other values may be specified by the National Annex per EN 1991-1-4 Section 4.4 (1) Expression (4.7) lv(z) = Iv(zmin) for z < zmin Mean wind velocity vm(z) = c r(z)*c 0(z)*vb per EN 1991-1-4 Section 4.4 (1) Expression (4.7) Iv(z) z (m) 0 5 - Zmin 5.5 10 20 25 30 35 40 45 50 - co(z) 0.355 0.344 0.285 0.238 0.226 0.217 0.210 0.204 0.200 0.195 cr(z) 1 1 1 1 1 1 1 1 1 1 per EN 1991-1-4 Section 4.4 (1) Expression (4.7) ce(z) qp (z) (kN/sqm) 1.281 1.337 1.709 2.182 2.344 2.479 2.596 2.700 2.792 2.876 0.720 0.720 0.752 0.961 1.227 1.318 1.395 1.460 1.519 1.570 1.618 0.606 0.627 0.755 0.905 0.953 0.992 1.025 1.054 1.079 1.102 References: EN 1991-1-4:2005 - Eurocode 1: Actions on structures - Part 1-4: General actions - Wind actions Height (m) Peak velocity pressure qp(z) = c e(z)*q b where ce(z) = [1+7*Iv(z)]*c r(z)*c o(z) 55 50 45 40 35 30 25 20 15 10 5 0 0.000 0.500 1.000 1.500 q(z) (kN/sqm) 2.000