1. Site Grading of Terrace
Norman W. Garrick
CE 4410 Spring Lecture 7

2. Terrace slopes 3/% down to top Side slopes in cut: 3:1 max
110
109.5
Terrace: 4 m by 5 m
Terrace slopes 3/% down to top
Side slopes in cut: 3:1 max
107.0
107.5
108.0
108.1
108.1
108.5
109.0
4 m
109.5

3. 110
109.5
107.0
107.5
107.8
107.8
108.0
108.1
108.1
108.5
109.0
4 m
109.5

4. Contour 108.5 is 1.2 m from Point A
110
109.5
Contour is 1.2 m from Point A
107.0
107.5
107.8
107.8
108.0 A
108.1
108.1
108.5
109.0
4 m
109.5

5. Contour 109 is 2.7 m from Point A
110
109.5
Contour 109 is 2.7 m from Point A
107.0
107.5
107.8
107.8
108.0 A
108.1
108.1
108.5
109.0
4 m
109.5

6. Contour 108 crosses the terrace
110
109.5
Contour 108 crosses the terrace
107.0
107.5
107.8
107.8
108.0 A
108.1
108.5
109.0
4 m
109.5

7. Contour 109.5 is 4.2 m from Point A
110
109.5
Contour is 4.2 m from Point A
107.0
107.5
107.8
107.8
108.0 A
108.1
108.1
108.5
109.0
4 m
109.5

8. Same relationship for Point B
110
109.5
Same relationship for Point B
107.0
107.5
107.8
107.8
108.0 A B
108.1
108.1
108.5
109.0
4 m
109.5

9. 110
109.5
Repeat for C and D
107.0
107.5
107.8
107.8
108.0 A B
108.1
108.1
108.5
109.0
4 m
109.5

10. 110
109.5
Draw Contour 108
107.0
107.5
107.8
107.8
108.0 A B
108.1
108.1
108.5
109.0
4 m
109.5

11. 110
109.5
Draw Contour 108.5
107.0
107.5
107.8
107.8
108.0 A B
108.1
108.1
108.5
109.0
4 m
109.5

12. 110
109.5
Draw Contour 109
107.0
107.5
107.8
107.8
108.0 A B
108.1
108.1
108.5
109.0
4 m

13. 110
109.5
107.0
107.5
108.0
108.5
109.0
Draw Contour 109.5
107.8
107.8 A B
108.1
108.1
4 m

14. Complete Grading Plan 4 m 110 109.5 107.0 107.5 107.8 107.8 108.0 A B
108.1
108.1
108.5
109.0
4 m

15. 110
109.5
Any Design Issues?
107.0
107.5
107.8
107.8
108.0 A B
108.1
108.1
108.5
109.0
4 m

16. Creating a Diversion X X X 4 m 110 109.5 107.0 107.2 107.5 107.8 107.8
108.0 A
108.1
108.1
107.7
107.7 X X X
107.9
108.5
109.0
4 m
109.5

17. Complete the 108 ft Contour
110
109.5
Complete the 108 ft Contour
107.0
107.2
107.5
107.8
107.8
108.0 A
108.1
108.1
107.7
107.7 X X X
107.9
108.5
109.0
4 m
109.5

18. 110
109.5
108 Ft Contour Lines
107.0
107.2
107.5
107.8
107.8
108.0 A
108.1
108.1
107.7
107.7 X X X
107.9
108.5
109.0
4 m
109.5

19. Complete Grading with Diversion
110
109.5
Complete Grading with Diversion
107.0
107.2
107.5
107.8
107.8
108.0 A
108.1
108.1
107.7
107.7 X X X
107.9
108.5
109.0
4 m
109.5

20. Calculation of Cut and Fill

21. 110
109.5
107.0
107.5
108.0
108.5
109.0
106.5

22. 110
109.5
107.0
107.5
108.0
108.5
109.0
106.5 A B

23. Profile A - B
Proposed
Existing A B

24. 110
109.5
107.0
107.5
108.0
108.5
109.0
106.5
Limits of Cut and Fill

25. How do we Calculation Cut and Fill?
We look at three methods:
Average End Area Method
Contour Area Method
Borrow Pit Method

26. Average End Area Method
Typically used for linear projects such as roads, railroads, canals

27. Find area of Fill and Cut separately
for selected cross-sections
Volume of Fill (or cut) between
Two Cross-sections
= [(A1 + A2)/2 ] * L
Where:
A1 is area of fill for Cross-section 1
A2 is area of fill for Cross-section 2
L is distance between 1 and 2

28. A refinement to this approach is used
when A1 or A2 is an end cross-section
(there is not fill or cut)
In this case, (A1+A2)/2 * L
Over estimates the volume since
The shape of the earthwork is more
Like a pyramid.
In this case a more accurate formula Is
[(A1+A2)/3] * L
(Note there is an error in text for this formula)