Issue 12

This paper describes how values for snow load coefficients have been derived. The motivation for this work arose because the guidance on combination of actions given in the European Pre-standards on Actions differs from that given in the corresponding British Standards. The European Pre-standards use coefficients to reduce the variable action values used in combination design checks. At the time of writing (2000) British Standards do not specifically quote coefficients, but give different partial factors for each load type for different combinations. To produce a consistent approach across Europe a research group has investigated the values of these coefficients in respect of snow loading. This paper presents the analyses performed on UK and Eire meteorological data to determine values of these coefficients for use with snow loads. These values have been proposed for inclusion in the European Standard. Mary E. Brettle, BEng, Centre for Structural Engineering, BRE, Watford, UK Diana M. Currie, BSc(Eng), Formerly of BRE, Watford, UK Nicholas J. Cook, DSc(Eng), PhD, FRMetS, FICE, CEng, FIStructE, EurIng, Wind Engineering Consultant, St. Albans, UK

The current (2000) ground snow loading map for the UK in BS 6399: Part 3 is based on work carried out in the 1970s. During the development of the Eurocodes, the snow loads given by the National Standards were reviewed. A European research group was formed to produce a unified snow map for Europe. This paper discusses the extreme value analyses performed on UK and Eire meteorological data, the investigations to obtain a snow density relationship to convert snow depths to loads and their use to produce a new ground snow loading map. This map is currently being refined and has been proposed for inclusion in the European Standard on snow loading. Mary E. Brettle, BEng, Centre for Structural Engineering, BRE, Watford, UK Diana M. Currie, BSc, Formerly of BRE, Watford, UK