Steel Buildings in Europe

Part 3: Actions 3 - 19 The snow load shape coefficients that should be used for multi-span roofs are shown in Figure 7.3, where  1 and  2 are given in Table 7.1. Case (i) corresponds to the undrifted load arrangement. Case (ii) corresponds to the drifted load arrangement.  1  2 (i) (ii)       1 (  2 )  1 (  1 )  1 (  2 )  1  2  1 (  1 )  2 [(  1 +  2 )/ 2 ]  1 (  2 ) (i) Undrifted load arrangement (ii) Drifted load arrangement Figure 7.3 Snow load shape coefficient – Multi-span roof The snow load shape coefficients that should be used for roofs abutting to taller construction works are shown in Figure 7.4, where  1 ,  2 ,  s ,  w are given by the following expressions:  1 = 0,8 This value assumes that the lower roof is flat. If it is not, a specific study should be carried out by taking into account the direction of the slope.  2 =  s +  w where:  s is the snow shape coefficient due to sliding of snow from the upper roof. For  ≤ 15°,  s = 0 For  > 15°,  s = half the snow load on the adjacent slope of the upper roof  w is the snow load shape coefficient due to wind  w = ( b 1 + b 2 )/2 h with  w ≤    h / s k And the recommended range is (it may be given in the National Annex): 0,8 ≤  w ≤ 4 b 1 , b 2 and h are defined in Figure 7.4  is the weight density of snow for this calculation (2 kN/m 3 )