1. Check Beam Shear

2. Bending moment design
2.5m
245
166
Short direction

3. Central band ratio =
Central band of short direction = 0.83 As = 0.83 (10.1)=8.6cm2

5. Footing Design
Part II
Combined footing

6. Example 1
Design a combined footing As shown

7. Dimension calculation
The base dimension to get uniform distributed load
2000kN
800 kN
1200 kN A
x1=0.2m
x2=6.2m x
800(0.2)+1200(6.2)=2000(x)
x = 3.8m
800 kN
1200 kN
Try thickness =80cm
2x =7.6 m

8. Area required

9. Check for punching Shear
d = 730 mm
1.13m
0.765 A

10. B

11. Draw S.F.D & B.M.D
Stress under footing
= 190 *1.8 = 342 kN/m

12. Check for beam shear
b = 1800mm, d = 730mm

13. Bending moment Long direction

14. Bending moment Short direction
Under Column A

15. Shrinkage Reinforcement in short direction
Under Column B
Shrinkage Reinforcement in short direction

17. Combined footing, strip footing, & Mat foundation
Footing Design
Part III
Combined footing, strip footing, & Mat foundation

18. Example 2
Design a combined footing As shown

19. Dimension calculation
The base dimension to get uniform distributed load
x2=4.2m
1200 kN
750 kN x
1950kN A
750(4.2)+1200(0.2)=1950 (x)
x = 1.75m
x1=0.2m

20. Area required

21. Check for punching Shear
h= 750mm
d = 732 mm A
B2=1m
B1=4m

22. B

23. Draw S.F.D & B.M.D

24. Empirical S.F.D & B.M.D m Convert trapezoidal load to rectangle Mmax
Clear distance between column
B in moment design = ave. width = 2.5m

25. Check for beam shear
d = 665mm
Y=1.5m 1m 4m x b

26. Bending moment Long direction
Top
Bottom

27. Bending moment Short direction
Under Column A

28. Shrinkage Reinforcement in short direction
Under Column B
Shrinkage Reinforcement in short direction

29. Reinforcement details

30. Example 3 (Strip footing)
Design a combined footing As shown

31. Dimension calculation
The base dimension to get uniform distributed load
3040kN
800 kN
1280 kN
960 kN A
Assume
L1=0.6
x1=5.2m L2
x2=10.7m x
800(0.6)+1280(5.1)+960(10.6)=
3040 (x)
x = 5.65m,
2(x)=11.3m
L2= (10.6)=0.7

33. B Check for punching Shear h = 700 mm d=630mm Example
You can check other columns

34. Draw S.F.D & B.M.D
Stress under footing
= 195 *1.8 = 351 kN/m

35. Check for beam shear
b = 1800mm, d = 630mm

36. Bending moment Long direction
Design Short direction as example 1 (lecture 11)

37. Reinforcement details

38. Mat Foundation

40. Check for punching Shear

41. General Example, Ref. 2
Modified load

42. General reinforcement details