BS EN 1991-1-4:2005+A1:2010

EN 1991-1-4 gives guidance on the determination of natural wind actions for the structural design of building and civil engineering works for each of the loaded areas under consideration. This includes the whole structure or parts of the structure or elements attached to the structure, e. g. components, cladding units and their fixings, safety and noise barriers.

This Part is applicable to:

• Buildings and civil engineering works with heights up to 200 m, see also (11).

• Bridges having no span greater than 200 m, provided that they satisfy the criteria for dynamic response, see (12) and 8.2.

This part is intended to predict characteristic wind actions on land-based structures, their components and appendages.

Certain aspects necessary to determine wind actions on a structure are dependent on the location and on the availability and quality of meteorological data, the type of terrain, etc. These need to be provided in the National Annex and Annex A, through National choice by notes in the text as indicated. Default values and methods are given in the main text, where the National Annex does not provide information.

Annex A gives illustrations of the terrain categories and provides rules for the effects of orography including displacement height, roughness change, influence of landscape and influence of neighbouring structures.

Annex B and C give alternative procedures for calculating the structural factor cscd.

Annex D gives cscd factors for different types of structures.

Annex E gives rules for vortex induced response and some guidance on other aeroelastic effects.

Annex F gives dynamic characteristics of structures with linear behaviour

This part does not give guidance on local thermal effects on the characteristic wind, e.g. strong arctic thermal surface inversion or funnelling or tornadoes.

Guyed masts and lattice towers are treated in EN 1993-3-1 and lighting columns in EN 40.

This part does not give guidance on the following aspects:

• torsional vibrations, e.g. tall buildings with a central core

• bridge deck vibrations from transverse wind turbulence

• wind actions on cable supported bridges

• vibrations where more than the fundamental mode needs to be considered.