Steel Buildings in Europe

Title APPENDIX A. Worked Example: Snow load applied on a single-storey building 2 of 8 3 - 37 3. Snow load on the roof 3.1. General The loads act vertically and refer to a horizontal projection of the roof area. Two primary load arrangements shall be taken account:  undrifted snow load on roofs  drifted snow load on roofs EN 1991-1-3 §5.2(1) Snow loads on roofs are determined as follows:  Persistent (conditions of normal use)/transient (temporary conditions) design situations: s =  i C e C t s k EN 1991-1-3 § 5.2(3) a)  Accidental design situations (exceptional snow fall) where exceptional snow load is the accidental action: s =  i C e C t s Ad § 5.2(3) b)  Accidental design situations (exceptional snow drift) where the accidental action is the exceptional drift and where Annex B applies: s =  i s k § 5.2(3) c) where:  i is the snow shape coefficient EN 1991-1-3 § 5.3 C e is the exposure coefficient, C e = 1,0 § 5.2(7) C t is the thermal coefficient, C t = 1,0 § 5.2(8) 3.2. Upper roof (duo pitch roof) Angle of the roof (15%):  = arc tan (0,15) = 8,5° 0    30°  Persistent /transient design situations - Case (i) : undrifted load arrangement  1 (  = 8,5°) = 0,8 s = 0,8  0,65 = 0,52 kN/m 2 EN 1991-1-3 § 5.3.3 Figure 5.3 - Case (ii): Drifted load arrangement 0,5  1 (  = 8,5°) = 0,4 s = 0,4  0,65 = 0,26 kN/m 2 - Case (iii): Drifted load arrangement The case (iii) is symmetrical about the case (ii) because of the symmetry of the roof (  1 =  2 = 8,5°).