1. Beams

2. BEAMS
A structural member loaded in the transverse direction to the longitudinal axis.
Internal Forces:
Bending Moments and Shear

3. Stability

4. Stability

5. Stability

6. Stability

7. Stability

8. Stability

9. Stability

10. Stability

11. Stability

12. Stability

13. Stability

14. Stability

15. Stability

16. Stability

17. Stability

18. Stability

19. Stability

23. Structural Steel - Characteristics
Buckling: Instability due to slenderness

24. Stability

26. Elastic Buckling

27. Limit States

28. Limit States

29. Limit States

30. Limit States

31. Classification of Shapes
Compact Section
Non-Compact Section
Web Local Buckling
Flange Local Buckling

32. Bending Strength of Compact Shapes
Lateral Torsional Buckling

33. Bending Strength of Compact Shapes

34. Bending Strength of Compact Shapes
Laterally Supported Compact Beams

35. Bending Strength of Compact Shapes

36. Bending Strength of Compact Shapes
Elastic Buckling

37. Elastic Buckling
Cb = factor to account for non-uniform bending within the unbraced length
See AISC table 3-1 p 3.10
Mmax A B C
L/4
L/4
L/4
L/4

38. Elastic Buckling

39. Elastic Buckling

40. Elastic Buckling
Cb = factor to account for non-uniform bending within the unbraced length
Rm= 1 for doubly symmetric cross sections and singly symmetric subject to single curvature
See textbook p 190 for other cases

41. Elastic Buckling
Cb = factor to account for non-uniform bending within the unbraced length

42. Elastic Buckling
Cb = factor to account for non-uniform bending within the unbraced length
ho = distance between flange centroids = d-tf

43. Bending Strength of Compact Shapes

44. Bending Strength of Compact Shapes
Inelastic Buckling
Linear variation between Mp and Mr

45. Nominal Flexural Strength – Compact Shapes

46. Nominal Flexural Strength – NON-Compact Shapes
Most W- M- S- and C- shapes are compact
A few are NON-compact
NONE is slender
Webs of ALL hot rolled shapes in the manual are compact
FLB and LTB
Built-Up welded shapes can have non-compact or slender webs
FLB, WLB, LTB (AISC F4 and F5)

47. Nominal Flexural Strength – NON-Compact Shapes
WLB