Title prEN 1991-1-4_wm .pdf ✅

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM DRAFT prEN 1991-1-4 March 2024 ICS 91.010.30 Will supersede EN 1991-1-4:2005 English Version Eurocode 1 - Actions on structures - Part 1-4: Wind actions Eurocode 1 - Actions sur les structures - Partie 1-4 : Actions du vent Eurocode 1 - Einwirkungen auf Tragwerke - Teil 1-4: Windlasten This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 250. If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. This draft European Standard was established by CEN 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 CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and United Kingdom. Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation. Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard. EUROPEAN COMMITTEE FOR STANDARDIZATION C O M I T É E U R O P É E N D E N O R M A L I S A T I O N E U R O P Ä I S C H E S K O M I T E E F Ü R N O R M U N G CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels © 2024 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. prEN 1991-1-4:2024 E ΣΧΕΔΙΟ – ΔΗΜΟΣΙΑ ΚΡΙΣΗ
prEN 1991-1-4:2024 (E) 2 Contents Page European foreword ...................................................................................................................................................... 6 0 Introduction...................................................................................................................................................... 7 1 Scope..................................................................................................................................................................11 1.1 Scope of prEN 1991-1-4 ..............................................................................................................................11 1.2 Assumptions ...................................................................................................................................................11 2 Normative references..................................................................................................................................11 3 Terms, definitions and symbols ..............................................................................................................12 3.1 Terms and definitions................................................................................................................................. 12 3.2 Symbols ............................................................................................................................................................13 4 Design situations...........................................................................................................................................18 5 Modelling of wind actions..........................................................................................................................19 5.1 Representations of wind actions.............................................................................................................19 5.2 Classification of wind actions ...................................................................................................................19 5.3 Characteristic values ...................................................................................................................................19 5.4 Loading models..............................................................................................................................................19 5.5 Design assisted by testing and measurements ..................................................................................23 6 Wind velocity and velocity pressure......................................................................................................23 6.1 Basis for calculation.....................................................................................................................................23 6.2 Basic values.....................................................................................................................................................24 6.3 Mean wind velocity and pressure ...........................................................................................................25 6.4 Wind turbulence ...........................................................................................................................................29 6.5 Peak wind velocity and velocity pressure ...........................................................................................30 7 Wind actions ...................................................................................................................................................31 7.1 General..............................................................................................................................................................31 7.2 Choice of aerodynamic coefficient..........................................................................................................32 7.3 Wind pressure on surfaces........................................................................................................................32 7.4 Net pressure on surfaces............................................................................................................................33 7.5 Wind forces .....................................................................................................................................................33 8 Structural factor ccsd ....................................................................................................................................35 8.1 General..............................................................................................................................................................35 8.2 Approximate determination of ccsd ........................................................................................................35 8.3 Serviceability assessments........................................................................................................................38 9 Across-wind and torsional actions on buildings ...............................................................................38 10 Aeroelastic phenomena..............................................................................................................................38 10.1 General..............................................................................................................................................................38 10.2 Basis for calculation.....................................................................................................................................38 10.3 Galloping ..........................................................................................................................................................41 10.4 Divergence and flutter ................................................................................................................................41 10.5 Wake buffeting...............................................................................................................................................41 Annex A (informative) This page is left blank intentionally ......................................................................42 Editorial Note .................................................................................................................................................42 ΣΧΕΔΙΟ – ΔΗΜΟΣΙΑ ΚΡΙΣΗ
prEN 1991-1-4:2024 (E) 3 Annex B (informative) Terrain effects ...............................................................................................................43 Use of this annex ...........................................................................................................................................43 Scope and field of application ..................................................................................................................43 Illustrations of the upper roughness of each terrain category ....................................................43 Transition between terrain categories 0, I, II, III and IV ................................................................44 Orography coefficients ...............................................................................................................................46 Neighbouring structures............................................................................................................................51 Displacement height....................................................................................................................................52 Alternative wind model..............................................................................................................................53 Annex C (normative) Pressure coefficients for pressures on surface ....................................................56 Use of this annex ...........................................................................................................................................56 Scope and field of application ..................................................................................................................56 Pressure and force coefficients ...............................................................................................................56 Pressure coefficients for rectangular plan buildings ...................................................................... 57 Pressure coefficients for irregular buildings .....................................................................................84 Pressure coefficients for circular structures......................................................................................89 Internal pressures..................................................................................................................................... 101 Annex D (normative) Net pressure and force coefficients for walls, roofs and skins.................... 104 Use of this annex ........................................................................................................................................ 104 Scope and field of application ............................................................................................................... 104 Net pressure and force coefficients for canopy roofs, porches and balconies .................... 104 Net pressure coefficients for free-standing walls, parapets, fences and signboards........ 115 Annex E (normative) Force coefficients for structures and structural members ........................... 121 Use of this annex ........................................................................................................................................ 121 Scope and field of application ............................................................................................................... 121 General .......................................................................................................................................................... 121 Force coefficients for spheres ............................................................................................................... 130 Force coefficients for square and triangular lattice structures and scaffoldings .............. 132 Force coefficients for flags...................................................................................................................... 141 Force coefficients for iced structures................................................................................................. 142 Force coefficients for bridge decks ..................................................................................................... 146 Friction coefficients .................................................................................................................................. 155 Annex F (informative) Procedure for along-wind dynamic response................................................. 157 Use of this annex ........................................................................................................................................ 157 Scope and field of application ............................................................................................................... 157 Along-wind dynamic response ............................................................................................................. 157 ΣΧΕΔΙΟ – ΔΗΜΟΣΙΑ ΚΡΙΣΗ
prEN 1991-1-4:2024 (E) 4 Along-wind turbulence............................................................................................................................ 157 Constant sign mode shapes .................................................................................................................... 159 Background response factor.................................................................................................................. 166 Resonance response factor .................................................................................................................... 168 Peak factor for resonant response ...................................................................................................... 170 Non-constant sign mode shapes — Calculation of equivalent static wind force.................171 Number of loads for dynamic response............................................................................................. 175 Annex G (informative) Procedure for across-wind and torsional actions on susceptible buildings .......................................................................................................................................................................... 177 Use of this annex ........................................................................................................................................ 177 Scope and field of application ............................................................................................................... 177 General........................................................................................................................................................... 177 Detailed procedure for across-wind actions.................................................................................... 178 Detailed procedure for torsional actions.......................................................................................... 182 Simplified procedure for across-wind and torsional actions for square plan buildings . 185 Across-wind and torsional accelerations.......................................................................................... 187 Combination of actions and action effects ........................................................................................ 188 Annex H (informative) Procedure for across-wind dynamic and aeroelastic response of slender structures...................................................................................................................................................... 190 Use of this annex ........................................................................................................................................ 190 Scope and field of application ............................................................................................................... 190 General........................................................................................................................................................... 190 Across-wind dynamic response............................................................................................................ 191 Vortex shedding ......................................................................................................................................... 198 Galloping ....................................................................................................................................................... 210 Divergence and flutter ............................................................................................................................. 214 Annex I (informative) Dynamic characteristics of structures with linear elastic behaviour......219 Use of this annex ........................................................................................................................................ 219 Scope and field of application ............................................................................................................... 219 General........................................................................................................................................................... 219 Fundamental frequency .......................................................................................................................... 219 Fundamental mode shape....................................................................................................................... 226 Equivalent mass.......................................................................................................................................... 229 Logarithmic decrement of damping.................................................................................................... 229 Annex J (informative) Response of steel lattice towers and guyed masts..........................................232 Use of this annex ........................................................................................................................................ 232 Scope and field of application ............................................................................................................... 232 ΣΧΕΔΙΟ – ΔΗΜΟΣΙΑ ΚΡΙΣΗ