Steel Buildings in Europe

Title APPENDIX B. Worked Example: Wind action on a single-storey building 8 of 11 3 - 53 The most severe case is when the opening is in a zone where |c pe | is the highest (the door is completely in zone B). c pi = 0,90 c pe c pi = 0,90  -0,8 = -0,72 EN 1991-1-4 § 7.2.9(6) 4. Friction forces 4.1. Wind on gable The area of the external surfaces parallel to the wind is calculated by: 60  2  (6 + 8,25  2) = 2700 m 2 The area of the external surfaces perpendicular to the wind is: 2  2  16  (6 + 1) = 448 m 2 The area of the external surfaces parallel to the wind is higher than 4  area of external surfaces perpendicular to the wind: friction forces should be taken into account: EN 1991-1-4 § 5.3(4) 4 h = 32 m 2 b = 64 m 4 h < 2 b The friction forces apply on the area A fr : A fr = 2  (60 – 32)  (6 + 8,25  2) = 1260 m 2 EN 1991-1-4 § 7.5(3) For a smooth surface (steel): c fr = 0,01 and the friction force F fr (acting in the direction of the wind): F fr = c fr q p ( z e ) A fr = (0,01  66  1260) 10 -2 = 8,316 kN EN 1991-1-4 § 5.5(3) 4 h < 2 b The friction forces apply on the area A fr : A fr = 2  (60 – 32)  (6 + 8,25  2) = 1260 m 2 EN 1991-1-4 § 7.5(3) For a smooth surface (steel): c fr = 0,01 and the friction force F fr (acting in the direction of the wind): F fr = c fr q p ( z e ) A fr = (0,01  66  1260) 10 -2 = 8,316 kN EN 1991-1-4 § 5.5(3) 4.2. Wind on long side Area of external surfaces parallel to the wind < 4  area of external surfaces perpendicular to the wind: friction forces should not be taken account EN 1991-1-4 § 5.3(4)