Earthwork calculations and applications .ppt

Earthwork calculations and applications

1. Prof Awad S. Hanna


2. Prof Awad S. Hanna

Earthwork includes:
1.Excavation
2.Grading: Moving earth to change
elevation
3.Temporary shoring
4.Back fill or fill: Adding earth to raise
grade
5.Compaction: Increasing density
6.Disposal

3. Prof Awad S. Hanna

A. Job conditions
Material type
Water level and moisture content
Job size
Length of haul
Haul road condition (accessibility and
load restrictions)

4. Prof Awad S. Hanna

B. Management conditions
Equipment conditions and maintenance
practices
Skills of work force and management
Planning, supervision and coordination
of work.

5. Prof Awad S. Hanna


J ob Conditions**ExcellentGood Fair Poor
Excellent 0.84 0.81 0.76 0.70
Good 0.78 0.75 0.71 0.65
Fair 0.72 0.69 0.65 0.60
Poor 0.63 0.61 0.57 0.52
Management Conditions*

6. Prof Awad S. Hanna

Cubic Yard (bank, loose, or compacted)
Bank (BCY): Materials in its natural
state before disturbance
(in-place, in-situ)
Loose (LCY): Material that has been
compacted or disturbed
or loaded
Compacted (CCY):Material after compaction

7. Prof Awad S. Hanna
1.0
1.25
0.90
1.0 CUBIC
YARD IN
NATURAL
CONDITION
(IN-PLACE
YARD)
1.25 CUBIC
YARD AFTER
DIGGING
(LOOSE
YARDS)
0.90 CUBIC
YARD AFTER
COMPACTED
(COMPACTED
YARDS)
In place
CompactedLoose

8. Prof Awad S. Hanna

Bank: VB
Bank cubic yards (BCY)
Density B Lb /BCY
Loose: Vl
Loose cubic yards (LCY)
Density L Lb/LCY
Compacted: Vc
Compacted cubic yards (CCY)
Density C LB/CCY

9. Prof Awad S. Hanna
Swell:
A soil increase in volume when it is excavated.
Swell (%) = ( - 1) x 100
Load factor =
Bank Volume = Loose volume x Load factor
Loose density
Bank density
Bank density
Loose density

10. Prof Awad S. Hanna
Shrinkage:
A soil decreases in volume when it is
compacted
Shrinkage (%) = (1 - ) x 100
Shrinkage factor = 1 - Shrinkage
Compacted volume
= Bank volume x Shrinkage factor
Bank density
Compacted density

11. Prof Awad S. Hanna

Material
Loose
(lb/cy)
Bank
(lb/cy)
Swell
(%)
Load
Factor
Clay, dry 2,1002,650260.79
Clay, wet 2,7003,575320.76
Clay and gravel, dry2,4002,800170.85
Clay and gravel, wet2,6003,100170.85
Earth, dry 2,2152,850290.78
Earth, moist 2,4103,080280.78
Earth, wet 2,7503,380230.81
Gravel, wet 2,7803,140130.88
Gravel, dry 3,0903,620170.85
Sand, dry 2,6002,920120.89
Sand, wet 3,1003,520130.88
Sand and gravel, dry2,9003,250120.89
Sand and gravel, wet3,4003,750100.91
Exact values will vary with grain size, moisture content, compaction, etc.
Test to determine exact values for specific soils.

12. Prof Awad S. Hanna

Initial
Soil TypeSoil ConditionBank LooseCompacted
Clay Bank 1.00 1.27 0.90
Loose 0.79 1.00 0.71
Compacted 1.11 1.41 1.00
Common earthBank 1.00 1.25 0.90
Loose 0.80 1.00 0.72
Compacted 1.11 1.39 1.00
Rock (blasted)Bank 1.00 1.50 1.30
Loose 0.67 1.00 0.87
Compacted 0.77 1.15 1.00
Sand Bank 1.00 1.12 0.95
Loose 0.89 1.00 0.85
Compacted 1.05 1.18 1.00
Convrted to:

13. Prof Awad S. Hanna


Angle of Repose
2’-0”
or more

14. Prof Awad S. Hanna

For Sloping Sides of Excavation
Original
Ground Line
S
o
l
i
d

R
o
c
k
,

S
l
a
t
e

o
r

C
e
m
e
n
t
e
d

S
a
n
d

a
n
d

G
r
a
v
e
l
(
9
0

D
e
g
.
)
C
o
m
p
a
c
te
d
A
n
g
u
la
r
G
r
a
v
e
ls
1
/2
:1
(6
3
D
e
g
.)
R
e
c o
m
m
e
n
d
e
d
S
l o
p
e
f o
r A
v
e
r a
g
e
S
o
i l s
1
: 1
( 4
5
D
e
g
. )
C
o
m
p
acted
Sh
arp
San
d
1 1/2 :1 (33 D
eg
.)
W
ell Rounded Loose Sand
2:1 (26 D
eg.)

15. Prof Awad S. Hanna

1. End Area Method
2. Contour Line/ Grid Method

16. Prof Awad S. Hanna

Used in sites where length is much
greater than width

17. Prof Awad S. Hanna

1. End Area Method
a.Take cross-sections at regular intervals,
typically, 100’ intervals.
b.Calculate the cross-section end areas
c.The volume of earthwork between sections is
obtained by taking the average of the end
areas at each station in square feet multiplied
by the distance between sections in feet and
dividing by 27 to obtain the volume in cubic
yards.

18. Prof Awad S. Hanna

Fill
Cut
8
0
8
2
8
4
8
6
8
8
8
0
8
4
8
6
8
8
8
2
7
8
A’ B’ C’ D’ E’ F’
A B C D E F
100' 100' 100' 100' 100'
500'
3
0
0
'

19. Prof Awad S. Hanna
80
78
76
82
80
78
84
82
80
86
84
88
86
90
88
78.5
80.3
82.3
84.2
86.2
88.2
Sec. A’- A
Sec. B’- B
Sec. C’- C
Sec. D’- D
Sec. E’- E
Sec. F’- F
P
r
o
j
e
c
t

C
r
o
s
s

S
e
c
t
i
o
n
s

20. Prof Awad S. Hanna

80
79
78
77
76
79.5
78.5
76.7
Section A’- A
Area = = 173.7
193 x 1.8
2
Area = = 53.5
107 x 1.0
2

21. Prof Awad S. Hanna

82
81
80
79
78
81.8
80.3
76.7
Section B’- B
Area = = 189.0
210 x 1.8
2
Area = = 67.5
90 x 1.5
2

22. Prof Awad S. Hanna

SectionEmb (CCY)Exc. (BCY)Exc. x B/C
(CCY)
Net Exc.
(CCY)
Cum Exc
(CCY)
A-B 672 224 254 - 418 - 418
B-C 567 441 499 - 68 - 486
C-D 215 791 896 681 195
D-E 0 1031 1167 1167 1362
E-F 0 1222 1384 1384 2746

23. Prof Awad S. Hanna

Used for parking lots and site
“leveling”
Grid size from 10’x10’ to 50’x50’
the greater the terrain variance the
smaller the grid

24. Prof Awad S. Hanna

Step l
Determine by visual study of the site drawing if the net total
will be an import (more fill required than cut) an export (less
fill required than cut) or a blend (cut and fill about equal)
Step 2
Determine the pattern of calculation points or grid size.
Step 3
Determine elevations at each calculation location, the corners
of each grid.
Step 4
Calculate the cubic yards of cut or fill required in each grid
cell.
Step 5
Add the individual Grid Cell quantities together to arrive at
the total cut, total fill volume and the import or volume
export yardage required for the job.

25. Prof Awad S. Hanna
A B C D E F
87.6 88.6 89.4 90.4 91.6 93.2
G H J K L M
87.4 88.2 89.5 90.6 91.6 92.7
N O P Q R S
87.2 87.7 89.0 90.4 91.3 92.0
87.6 88.5 89.3 90.3 91.5 95.0
94.3
93.5
93.1
A B C D E F G
300’
88’ 89’ 90’ 91’92’ 93’ 94’
No Scale
Notes:
1. Bring the entire site to elevation 90.
2. All grids are 50’x 50’ = 2500 sq. ft.
3. Present contours

26. Prof Awad S. Hanna
Purpose
Grade the entire site to grade 90’
Quick and Dirty
Assume one grid
Existing90.50
Proposed90.00
Cut 0.50
Total Cost = = 833CY
150 x 300 x 0.50
27
300'
1
5
0
'Need
Fill
Need
Cut
90'
90' 91'
90.5'

27. Prof Awad S. Hanna
Average elevation
=
= 88.08
change= 90-88.08
= 1.92
cut =
= 177.77 CY
and so on.
If we choose the grid size to be 50’x50’
87.6+88.5+87.6+88.6
4
87.6
88.6
87.687.6