estimating earthwork - kontrak prosedur 2

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Page 1: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Page 2: Estimating Earthwork - kontrak prosedur 2

TazriAziz

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

Page 3: Estimating Earthwork - kontrak prosedur 2

TazriAziz

A. Job conditionsMaterial typeWater level and moisture contentJob sizeLength of haulHaul road condition (accessibility and

load restrictions)

Page 4: Estimating Earthwork - kontrak prosedur 2

TazriAziz

B. Management conditionsEquipment conditions and

maintenance practicesSkills of work force and managementPlanning, supervision and

coordination of work.

Page 5: Estimating Earthwork - kontrak prosedur 2

TazriAziz

J ob Conditions** Excellent Good 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*

Page 6: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Meter cube m3 (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

Page 7: Estimating Earthwork - kontrak prosedur 2

TazriAziz

1.0

1.25

0.90

1.0 METER CUBE IN NATURAL CONDITION (IN-PLACE YARD)

1.25 METER CUBE AFTER DIGGING (LOOSE YARDS)

0.90 METER CUBE AFTER COMPACTED (COMPACTED YARDS)

In place CompactedLoose

Page 8: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Bank: VB

Bank Meter Cube (BMC)Density B Lb /BMC

Loose: VL

Loose Meter Cube (LMC)Density L Lb/LMC

Compacted: Vc

Compacted Meter Cube (CMC)Density C LB/CMC

Page 9: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Swell:A soil increase in volume when it is excavated.

Swell (%) = ( - 1) x 100

Load factor =

Bank Volume = Loose volume x Load factor

Loose densityBank density

Bank densityLoose density

Page 10: Estimating Earthwork - kontrak prosedur 2

TazriAziz

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 densityCompacted density

Page 11: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Material

Loose

(kg/m3)

Bank

(kg/m3)Swell (%)

Load Factor

Clay, dry 1,604 2,024 26 0.79Clay, wet 2,062 2,731 32 0.76Clay and gravel, dry 1,833 2,139 17 0.85Clay and gravel, wet 1,986 2,368 17 0.85Earth, dry 1,693 2,177 29 0.78Earth, moist 1,841 2,353 28 0.78Earth, wet 2,101 2,582 23 0.81Gravel, wet 2,123 2,398 13 0.88Gravel, dry 2,360 2,765 17 0.85Sand, dry 1,986 2,230 12 0.89Sand, wet 2,368 2,689 13 0.88Sand and gravel, dry 2,215 2,483 12 0.89Sand and gravel, wet 2,597 2,865 10 0.91

Exact values will vary with grain size, moisture content, compaction, etc. Test to determine exact values for specific soils.

Page 12: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Initial

Soil Type Soil Condition Bank Loose CompactedClay Bank 1.00 1.27 0.90

Loose 0.79 1.00 0.71Compacted 1.11 1.41 1.00

Common earth Bank 1.00 1.25 0.90Loose 0.80 1.00 0.72Compacted 1.11 1.39 1.00

Rock (blasted) Bank 1.00 1.50 1.30Loose 0.67 1.00 0.87Compacted 0.77 1.15 1.00

Sand Bank 1.00 1.12 0.95Loose 0.89 1.00 0.85Compacted 1.05 1.18 1.00

Convrted to:

Page 13: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Angle of Repose2’-0”or more

Page 14: Estimating Earthwork - kontrak prosedur 2

TazriAziz

For Sloping Sides of Excavation

OriginalGround Line

Solid

Rock

, Sla

te o

r C

em

ente

d S

and a

nd G

ravel

(90

Deg.)

Com

pact

ed A

ngul

ar G

rave

ls

1/2:

1 (6

3 D

eg.)

Reco

mm

ende

d Sl

ope

for A

vera

ge S

oils

1:1

(45

Deg.)

Compacted Sharp

Sand

1 1/2 :1 (3

3 Deg.)

Well Rounded Loose Sand

2:1 (26 Deg.)

Page 15: Estimating Earthwork - kontrak prosedur 2

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1. End Area Method

2. Contour Line/ Grid Method

Page 16: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Used in sites where length is much greater than width

Page 17: Estimating Earthwork - kontrak prosedur 2

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1. End Area Method

a.Take cross-sections at regular intervals, typically, 10m 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 meter.

Page 18: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Fill

Cut

80

82

84

86

88

80

84

86

88

82

78

A’ B’ C’ D’ E’ F’

A B C D E F10 10 10 10 10

50m

30

m

Page 19: Estimating Earthwork - kontrak prosedur 2

TazriAziz

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

Pro

ject

Cro

ss S

ect

ion

s

Page 20: Estimating Earthwork - kontrak prosedur 2

TazriAziz

80

79

78

77

76

79.5

78.5

76.7

Section A’- A

Area = = 173.7193 x 1.8

2

Area = = 53.5107 x 1.0

2

Page 21: Estimating Earthwork - kontrak prosedur 2

TazriAziz

82

81

80

79

78

81.8

80.3

76.7

Section B’- B

Area = = 189.0210 x 1.8

2

Area = = 67.590 x 1.5

2

Page 22: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Section Emb (CCY) Exc. (BCY) Exc. x B/C(CCY)

Net Exc.(CCY)

Cum Exc(CCY)

A-B 672 224 254 - 418 - 418B-C 567 441 499 - 68 - 486C-D 215 791 896 681 195D-E 0 1031 1167 1167 1362E-F 0 1222 1384 1384 2746

Page 23: Estimating Earthwork - kontrak prosedur 2

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Used for parking lots and site “leveling”

Grid size from 10mx10m to 50mx50m

the greater the terrain variance the smaller the grid

Page 24: Estimating Earthwork - kontrak prosedur 2

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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 2Determine 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 5Add 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.

Page 25: Estimating Earthwork - kontrak prosedur 2

TazriAziz

A B C D E F87.6 88.6 89.4 90.4 91.6 93.2

G H J K L M87.4 88.2 89.5 90.6 91.6 92.7

N O P Q R S87.2 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 G60m

88’ 89’ 90’ 91’ 92’ 93’ 94’

No ScaleNotes:1. Bring the entire site to elevation 90.2. All grids are 10m x 10m = 100 sq m3. Present contours

Page 26: Estimating Earthwork - kontrak prosedur 2

TazriAziz

PurposeGrade the entire site to grade 90’

Quick and DirtyAssume one gridExisting 90.50Proposed 90.00Cut 0.50

Total Cost = = 1.851m310 x 10 x 0.5027

10m

10

m

NeedFill

Need

Cut

90'

90' 91'

90.5'

Page 27: Estimating Earthwork - kontrak prosedur 2

TazriAziz

Average elevation

=

= 88.08change = 90-88.08

= 1.92m3

If we choose the grid size to be 10mx10m

87.6+88.5+87.6+88.64

87.6

88.6

87.687.6