EN 1991-1-4: Eurocode 1: Actions on structures - Part 1-4 ...

1 The European UnionIn order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to know and speak the laws that govern them. EDICT OF GOVERNMENT EN 1991-1-4 (2005) (English): Eurocode 1: Actions onstructures - Part 1-4: General Actions - Wind Actions [Authority: The European Union Per Regulation 305/2011,Directive 98/34/EC, Directive 2004/18/EC]EUROPEAN STANDARD NORME EUROPEENNE EN 1991-1-4: 2005+A 1 EUROpAISCHE NORM April 2010 ICS English version Supersedes ENV 1991-2-4:1995 Incorporating corrigendum January 2010 Eurocode 1: Actions on structures -Part 1-4: General Actions -Wind Actions Eurocode 1: - Actions sur les structures - Partie 1-4: Eurocode 1: Einwirkungen auf Tragwerke TeiI1-4.

2 Actions generales - Actions du vent Allgemeine Einwirkungen - Windlasten This European Standard was approved by CEN on 4 June 2004. CEN members are bound to comply with the CEN/CENELEC Intemal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions.

3 CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, luxembourg , Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMITE EUROPEEN DE NORMALISA nON EUROpAISCHES KOMlTEE FUR NORMUNG Management Centre: Avenue Marnix 17, B-1 000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

4 Ref. No. EN 1991-1-4: 2005: E BS EN 1991-1-4: 2005+A 1 :2010 EN 1991-1-4: 2005+A1 :2010 (E) Contents Section 1 General Scope Normative references Assumptions Distinction between Principles and Application Rules Design assisted by testing and measurements Definitions Symbols Section 2 Design situations Section 3 Modelling of wind Actions Nature Representations of wind Actions Classification of wind Actions Characteristic values Models Section 4 Wind velocity and velocity pressure Basis for calculation Basic values Mean wind Variation with height Terrain roughness Terrain orography Large and considerably higher neighbouring

5 structures Closely spaced buildings and obstacles Wind turbulence Peak velocity pressure Section 5 Wind Actions General Wind pressure on surfaces Wi nd forces Section 6 Structural factor cscd General Determination of cscd Detailed procedure Structural factor CsCd Serviceability assessments Wake buffeting Section 7 Pressure and force coefficients 2 General Choice of aerodynamic coefficient Asymmetric and counteracting pressures and forces Effects of ice and snow Pressure coefficients for buildings General Vertical walls of rectangular plan buildings Flat roofs Monopitch roofs Duopitch roofs Hipped roofs Multispan roofs Vaulted roofs and domes Page 9 9 10 10 10 10 10 11 16 17 17 17 17 17 17 18 18 18 19 19 19 21 21 22 22 22 24 24 24 25 28 28 28 28 28 30 30 31 31 31 32 32 33 33 34 37 40 43 47 48 50 BS EN 1991-1-4: 2005+A1:2010 EN 1991-1-4: 2005+A1.

6 2010 (E) Internal pressure 51 Pressure on walls or roofs with more than one skin 53 Canopy roofs 54 Free-standing walls, parapets, fences and signboards 61 Free-standing walls and parapets 61 Shelter factors for walls and fences 63 Signboards 63 Friction coefficients 64 Structural elements with rectangular sections 65 Structural elements with sharp edged section 67 Structural elements with regular polygonal section 67 circular cylinders 69 External pressure coefficients 69 Force coefficients 71 Force coefficients for vertical cylinders in a row arrangement 74 Spheres 74 Lattice structures and scaffoldings 76 Flags 78 Effective slenderness A and end-effect factor fJlJ.

7 80 Section 8 Wind Actions on bridges 82 General 82 Choice of the response calculation procedure 85 Force coefficients 85 Force coefficients in x-direction (general method) 85 Force in x-direction - Simplified Method 88 Wind forces on bridge decks in z-direction 89 Wind forces on bridge decks in y-direction 90 Bridge piers 91 Wind directions and design situations 91 Wind effects on piers 91 Annex A (informative) Terrain effects 92 Illustrations of the upper roughness of each terrain category 92 Transition between roughness categories 0, I, II, III and IV 93 Numerical calculation of orography coefficients 95 Neighbouring structures 100 Displacement height 101 Annex B (informative) Procedure 1 for determining the structural factor CsCd 102 Wind turbulence 102 Structural factor 103 Number of loads for dynamic response 105 Service displacement and accelerations for serviceability assessments of a vertical structure 105 Annex C (informative)

8 Procedure 2 for determining the structural factor CsCd 108 Wind turbulence 108 Structural factor 108 Number of loads for dynamic response 109 Service displacement and accelerations for serviceability assessments 109 Annex D (informative) CsCd values for different types of structures 111 Annex E (informative) Vortex shedding and aeroelastic instabilities 114 Vortex shedding 114 General 114 Criteria for vortex shedding 114 Basic parameters for vortex shedding 115 Vortex shedding action 118 Calcu lation of the cross wind amplitude 118 Measures against vortex induced vibrations 128 Galloping 129 General 129 3 BS EN 1991-1-4: 2005+A1:2010 EN 1991-1-4: 2005+A 1.

9 2010 (E) Onset wind velocity Classical galloping of coupled cylinders Interference galloping of two or more free standing cylinders Divergence and Flutter General Criteria for plate-like structures Divergency velocity Annex F (informative) Dynamic characteristics of structures General Fundamental frequency Fundamental mode shape Equivalent mass logarithmic decrement of damping Bibliography 4 129 131 133 134 134 134 134 136 136 136 141 143 143 146 Foreword BS EN 1991-1-4: 2005+A1:2010 EN 1991-1-4: 2005+A 1 :2010 (E) This document EN 1991-1-4: 2005 has been prepared by Technical Committee CEN/TC250 nStructural Eurocode ", the secretariat of which is held by BSI.

10 This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2005, and conflicting national standards shall be withdrawn at the latest by March 2010. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, luxembourg , Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.