1. EN 1991-1-4 : Wind actions Prof
EN : Wind actions Prof. Pierre SPEHL Technical Control Bureau for Construction

2. Contents of EN

3. 1.1 Scope

4. Storm of 25 Januari 1990

5. 4. Basic wind velocity vb

6. Fundamental value vb,0 of the basic wind velocity

7. Wind velocity measured in BEAUVECHAIN airport (Belgium) on 25 Januari 1990 (knots)

8. Wind velocity measured in BRUSSELS (Belgium) on 25 Januari 1990 (knots)

9. Annex A : Terrain roughness (categories 0, I et II)

10. Annex A : Terrain roughness (categories III & IV)

11. 4.3. Mean wind velocity vm(z)

12. Table 4.1 : Terrain parameters

13. Figure 4.1 : Assessment of terrain roughness

14. Transition between roughness categories

15. Upstream distance x (m) (National Annex of Belgium, France & Luxembourg)

16. Orography factor co

17. Wind deviation around a building

18. Neighbouring structures

19. 4.5. Peak velocity pressure qp(z)

20. Exposure factor ce(z)

21. 5.2. Wind pressure on surfaces

22. Reference height for external pressure ze (Figure 7.4)

23. Reference height for external pressure ze (Figure 7.4)

24. Zones for vertical walls (figure 7.5)

25. External pressure coefficient cpe for vertical walls (figure 7
External pressure coefficient cpe for vertical walls (figure 7.2 & Table 7.1)

26. Conical vortices (flat roof)

27. Zones on a monopitch roof (figure 7.7)

28. External pressure coefficient cpe for monopitch roofs (Table 7.3a)

29. Conical vortices (duopitch roof)

30. Wind tunnel testing (Central station Antwerp)

31. 5.3. Wind forces

32. 7.6. Force coefficient cf (figure 7.23 & 7.24)

33. Plane lattice structure with angle members (figure 7.33)

34. End effect factor yl (Figure 7.36)

35. 6. Structural factor cscd

36. Annex D : Structural factor

37. 6. Structural factor cscd

38. Background factor B²

39. Resonance factor R²

40. Aerodynamic admittance function

41. Power spectral density function SL (figure B.1)

42. Peak factor kp (figure B.2)

43. Vortex shedding (Annex E)

44. Critical wind velocity vcrit,i

45. Viaduc de MILLAU

46. Thank’s for your attention