The New Slovak National Annex STN EN 1991-1-3/NA1 General Actions. Snow loads: 2012

Significant changes introduced into the new Slovak National Annex STN EN 1991-1-3/NA1 General actions. Snow loads: 2012 are based on results of two subsequent projects completed within the period 2006 to 2010. The projects aimed at retrieving, assembling and processing of long-term meteorological data related to snow loads, statistical analysis of the data, map applications and studies focusing on probabilistic design, verification and optimisation of safety factors of structures subjected mainly to snow loads. The new map of characteristic snow loads on the ground employs altitude functions rather than a set of contour lines in the antecedent National Annex (2004). The exceptional snow loads are analysed by an original approach assessing the accidental snow loads on the ground as fractiles of the mean return period of 10000 years within delimited four distinct regions in Slovakia. Approximate formulas for determination of frequent and quasi-permanent value of snow load are developed. Probabilistic optimisation of safety factors resulted in increased snow load partial factor for the design and verification of the frames of low-rise halls with light-weight roofs. Analogous feature of the Czechoslovakian Standard ČSN 73 0035 (1988) was in the preceding National Annex omitted. The maps of characteristic and accidental snow loads are provided in printed version as well as in an interactive form on CD.