dr. nabil dmaidi e stimating e arthwork. dr. nabil dmaidi estimating earthwork earthwork includes: n...
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DR. Nabil Dmaidi
ESTIMATING EARTHWORK
ESTIMATING EARTHWORK
DR. Nabil Dmaidi
Estimating Earthwork
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
DR. Nabil Dmaidi
Productivity FactorsProductivity Factors
A. Job conditions– Material type– Water level and moisture content– Job size– Length of haul– Haul road condition (accessibility and load
restrictions)
DR. Nabil Dmaidi
Productivity Factors (cont.)Productivity Factors (cont.)
B. Management conditions– Equipment conditions and maintenance
practices– Skills of work force and management– Planning, supervision and coordination of
work.
DR. Nabil Dmaidi
Job Efficiency Factors for Earthmoving OperationsJob Efficiency Factors for Earthmoving Operations
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*
DR. Nabil Dmaidi
Units of Measure Units of Measure Cubic Yard (bank, loose, or compacted)
Bank (BCY): Material 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
DR. Nabil Dmaidi
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
DR. Nabil Dmaidi
VolumeVolumeBank: 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
DR. Nabil Dmaidi
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
DR. Nabil Dmaidi
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
DR. Nabil Dmaidi
Approximate Material CharacteristicsApproximate Material Characteristics
MaterialLoose (lb/cy)
Bank (lb/cy)
Swell (%)
Load Factor
Clay, dry 2,100 2,650 26 0.79Clay, wet 2,700 3,575 32 0.76Clay and gravel, dry 2,400 2,800 17 0.85Clay and gravel, wet 2,600 3,100 17 0.85Earth, dry 2,215 2,850 29 0.78Earth, moist 2,410 3,080 28 0.78Earth, wet 2,750 3,380 23 0.81Gravel, wet 2,780 3,140 13 0.88Gravel, dry 3,090 3,620 17 0.85Sand, dry 2,600 2,920 12 0.89Sand, wet 3,100 3,520 13 0.88Sand and gravel, dry 2,900 3,250 12 0.89Sand and gravel, wet 3,400 3,750 10 0.91
Exact values will vary with grain size, moisture content, compaction, etc. Test to determine exact values for specific soils.
DR. Nabil Dmaidi
Typical Soil Volume Conversion FactorsTypical Soil Volume Conversion Factors
InitialSoil Type Soil Condition Bank Loose Compacted
Clay Bank 1.00 1.27 0.90Loose 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:
DR. Nabil Dmaidi
Estimating Earth work for Trenches and FoundationsEstimating Earth work for Trenches and Foundations
Angle of Repose2’-0”or more
DR. Nabil Dmaidi
Approximate Angle of ReposeApproximate Angle of ReposeFor 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.)
DR. Nabil Dmaidi
Calculating Earthwork QuantitiesCalculating Earthwork Quantities
1.End Area Method
2.Contour Line/ Grid Method
DR. Nabil Dmaidi
1. End Area Method1. End Area Method
Used in sites where length is much greater than width
DR. Nabil Dmaidi
CALCULATING EARTHWORK QUANTITIESCALCULATING EARTHWORK QUANTITIES
1. End Area Methoda. 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.
DR. Nabil Dmaidi
Project Site Showing 100 StationsProject Site Showing 100 Stations
Fill
Cut
80
82
84
86
88
80
84
86
88
82
78
A’ B’ C’ D’ E’ F’
A B C D E F100' 100' 100' 100' 100'
500'
30
0'
DR. Nabil Dmaidi
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
DR. Nabil Dmaidi
Cross-Section @ A’- ACross-Section @ A’- A
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
DR. Nabil Dmaidi
Cross-Section @ B’- BCross-Section @ B’- B
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
DR. Nabil Dmaidi
Table 1. Cumulative Earthwork Quantities Table 1. Cumulative Earthwork Quantities
Section
Emb (CCY)
Exc. (BCY)
Exc. x c (CCY) C= 0.9
Net Exc. (CCY)
Cum Exc (CCY)
A-B 672 224 202 - 470 - 470 B-C 567 441 397 - 170 - 640 C-D 215 791 712 497 - 143 D-E 0 1031 928 928 785 E-F 0 1222 1100 1100 1885
DR. Nabil Dmaidi
2. Contour Line/ Grid Method2. Contour Line/ Grid Method
Used for parking lots and site “leveling” Grid size from 10’x10’ to 50’x50’ the greater the terrain variance the smaller
the grid
DR. Nabil Dmaidi
2. CONTOUR LINE/GRID CELL METHOD(cont.)2. CONTOUR LINE/GRID CELL METHOD(cont.)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.
DR. Nabil Dmaidi
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 G300’
88’ 89’ 90’ 91’ 92’ 93’ 94’
No ScaleNotes:1. Bring the entire site to elevation 90.2. All grids are 50’x 50’ = 2500 sq. ft.3. Present contours
DR. Nabil Dmaidi
PurposeGrade the entire site to grade 90’
Quick and DirtyAssume one gridExisting 90.50Proposed 90.00Cut 0.50
Total Cost =
= 833CY150 x 300 x 0.5027
300'
15
0'Need
FillNeedCut
90'
90' 91'
90.5'
DR. Nabil Dmaidi
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+88.64
87.6
88.6
87.687.6