lecture 3a-earthwork & ms diagram 2

8/17/2019 Lecture 3A-Earthwork & MS Diagram 2

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Earthwork Activities

A) Site clearing & grubbing


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A) Site clearing & grubbing • removal of trees, shrubs, and other vegetation

• removing stumps and root mat at least 600mm

below sub-grade


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B) Stripping Top Soil (to be done after site clearing)

• Top soil - resulting from decomposition of vegetative matter -

unsuitable for use in embankment- Strip the top soil eg 150mm thick as mentioned in BQ/

drawings – stockpile - to be used for turfing work/ landscape

or to waste

• Some project, stripping of top soil is given as a separate item(Quantity as ‘Lump Sum’ or using rate ‘per meter square’) and

some used as part of the excavation

Eg Description in BQ:

‘Strip top soil to an average depth of 150mm and stockpilesfor reuse or dispose …… m2 or hectars


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B) Stripping Top Soil


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C) Excavation & Embankment

Description in BQ eg

1) Excavate all the unsuitable material until hard formation and

refill with suitable matls as shown in the drawings and as

directed by the SO all in accordance with the specifications

…… m3 (quantity)

2) Excavation (earth) and transport as shown in the drawingsand as directed by the SO all in accordance with the

specifications …… cu.m

3) Excavation in rock …. cu.m (Prov Quantities ?)

4) Form embankment to the slope and levels as shown in thedrawings from excavated materials and as directed by the SO

all in accordance with the specifications …… cu.m


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Graphical Presentation of earthwork:

3 kinds of views in the contract documents to show

construction features

1. Plan view – horizontal alignment of features (for roads, drainages,sewwerage etc)

2. Profile view (longitudinal section) – a vertical view – along the centreline of the work (for roads, drainages & sewerage)

3. Cross section view – a view formed by a plane cutting the work atright angles to its horizontal alignment (in plan) – for a road project the

cross section at every 50 meter or other suitable intervals – for a building

project, cross sections across building platform for few locations both

along X axis and Y axis

(Section X-X and Section Y-Y)

Earthwork for Road projects - Drawings 1, 2 and 3 are given in Contract

document

Earthwork of building projects - Drawings 1 and 3 are given


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Figure 2.2 -Profile View (Longitudinal Section) pg 23

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Formationlevel

Existing

Ground

Level


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Figure 2.3 – Earthwork Cross Sections (pg 66)

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Plateform Level

Existing

Ground Level


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Cross Sections- Cut and Fill


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Earthwork Quantities:

Earthwork computation involve:1. Balancing cuts and fills

2. Calculating earthwork volume3. Planning the most economical material hauls – to left or right ?

1. Calculating earthwork volume:

Calculate a cross sectional end areasa) Use computer softwares or digitizing tablet

b) Use a planimeter (to measure are of cut or fill )

c) Sub divide of the project area into geometric figures eg

triangles, squares or rectangulars and the use of the trapezoidal formula- Triangle =1/2 hw

- Trapezoid = (h1+h2)x w where w= distance between 2 parallel sides

h1 & h2 lengths of the parellel sides

• Average end area = (A1 + A2)/2 in m2

• Volume = A1+A2 L/2 in m3


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Fig. 2.4 Cross Sectional Area- Division of a cross

section drawing into triangles & trapezoidals -(pg 68)

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Existing

Ground

Level

Formation

level


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Volume Calculation – Average end area (pg 69)

Volume = (A1+A2)/2 x L

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Calculation of Volume 1 – Example 3.2 ms 70

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Volume Calculation 2 (pg 70)

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Calculating earthwork volume:

Example 1: Volume = 257,018 ccy

Example 2: Volume = 250,556 ccy

Same project but different in volume is due to

- In Example 1 – more cross-sectional areas are

taken ( 9 end areas) compare to Example 2 (only 7

end areas )

You will get accurate answer if you take more cross

sections !


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Net Volume• Volume of material in cut is different with volume of material in

fill

• Volumes for the fill = compacted volume= c meter cube

• Volumes from the cut = natural volume (in situ volume) = bankvolume = b meter cube

• If the cut and fill volumes are to be combined, they must be

converted into compatible volume

• b= (c meter cube)/0.9 …… Refer Table 3.1 Peurifoy pg 73

Table 2.1 Earthwork Vol.xls

Table 3 1 Earthwork Volume Calculation Sheet

http://localhost/var/www/apps/conversion/tmp/scratch_3/Table%202.1%20Earthwork%20Vol.xlshttp://localhost/var/www/apps/conversion/tmp/scratch_3/Table%202.1%20Earthwork%20Vol.xls


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Table 3.1 – Earthwork Volume Calculation SheetTable 3.1.docx

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http://localhost/var/www/apps/conversion/tmp/scratch_3/Table%202.3.docxhttp://localhost/var/www/apps/conversion/tmp/scratch_3/Table%202.3.docx


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Calculating earthwork volume:An Earthwork volume sheet – refer Table 3.1

• Column 1 – Stations refer to surveyor notation (chainages) at 100 ft

interval (abt 30 m)

Distance between Stations = 50 ft or 100 ft (15 m or 30m)• Column 2 - End Area Cut (ft square) or meter sq – calculate cross

sectional areas in cut cros sectional in cut

• Column 3 - End Area Fill (ft square) – meter sq – calculate cros sectional

areas in fill

• Column 4 - Volume of Cut between the adjacent preceding stn and the

stn - Use average end area formula – (A1+A2)/2 x L = b cubic

meter ( in the example they used yd cube) , b= bank volume

• Column 5 - Volume of Fill – use avg end area formula = c cubic meter(m3) where c= compacted volume

• Column 6 – Stripping vol in the cut – width of cut x avg depth x distance

between stns = b cubic meter, not suitable for use in

embankment (will be deducted)



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Calculating earthwork volume: An Earthwork volume sheet – refer Table 3.1 …. Continue

• Column 7- Stripping volume in the fill – width of fill x avg depth x distance

between stn = c cubic meter• Column 8 - Total vol of cut = vol of cut (column 4 – vol of stripping cut in

col 6 = b cubic meter

• Column 9 - Total Fill = vol of fill in column 5 + vol of stripping fill in col 7

= c m3

• Column 10 – Adjusted Fill = total fill vol converted from compacted vol to

bank volumn (bcm) (m3) c m3/0.9 = b m3

• Column 11 – Algebraic Sum = vol in col 8 – vol in col 10 , + ve cut, -ve fill

= b m3

• Column 12 – Mass Ordinate = the running total of col 11, +ve cut, -ve fill

( cut will be added and fill will be substracted)

E th k V l & M Di (MD)


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Earthwork Volume & Mass Diagram (MD)

Table 3.1 pg 73

• Earth moving = operation where material is removedfrom high spots (cut) & deposited in low spots (fill) –

any deficit to get from borrow & excess to dump

M Di (MD)


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Mass Diagram (MD)

• MD is the most effective tools for planning movement

of material on any project of linear extent

• a graphical means for measuring haul distance inmeters (stations) and earthwork volume in m3

• the movement = 1 cubic meter, through a distance of

one station• Mass diagram only for matl that must be transported

beyond the limit of 2 cross section (200 ft or 100m)

• If having both cut & fill between stations, cut matl will

be used for fill requirement between 2 consecutive

stns. Only the excess vol is to be carried forward for

MD

M Di (MD)


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Mass Diagram (MD)

• An Earthwork Profile is a plot of the net earthwork

along a roadway or airstrip

• Net cut values are plotted above the X-axis (positive Yvalue)

• Net fill values are plotted below the X-axis (negative Y

value)• Presents a picture of the earthwork requirements

Figure 2 6 (pg 76 A Mass Diagram


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Figure 2.6 (pg 76 – A Mass Diagram

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Highest pt in MD at the end

of cut & beginning of fill

Existing

Ground

Level

Formation

level

Lowest pt in

MDat the end of

fill and beginningof cut

M Di (MD)


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Mass Diagram (MD)

M Di (MD)


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Mass Diagram (MD)

• A Mass Haul Diagram is a con t inuous curve

represent ing the cumulat ive volum e of ear thwork

along the l inear prof i le of a roadway or air f ield

• The accumulated volume of earthwork at the

horizontal axis (Y=0) is 0

• When a horizontal line intersects two or more pointsalong the curve, the accumulated volumes at those

points are equal

• A negative value at the end of the curve indicates that

borrow is required to complete the fill• A positive value at the end of the curve indicates that

a waste operation will be the net result


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Mass Diagram (MD)


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Mass Diagram (MD)

• The accumulated volume of earthwork at the

horizontal axis (Y=0) is 0

• When a horizontal line intersects two or more

points along the curve, the accumulated

volumes at those points are equal

• A negative value at the end of the curve

indicates that borrow is required to complete

the fill

• A positive value at the end of the curve

indicates that a waste operation will be the net

result

Mass Diagram (MD)


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Mass Diagram (MD)

• Table 3.1 –

Column (1) is Stations of a project (Chainage)

Column (12) is cumulative sum of excavation &embankment

• The Table 2.1 gives information on:

1) Quantities of matl, 2) Avg haul distance,3) Types of equipment to be considered

• Refer Figure 3.13 Peurifoy pg 76, For Mass Diagram,+ ve mass ordinate above datum = volume of matl is

surplus

- ve below datum = volume of mtl is deficient

Mass Diagram Properties


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Mass Diagram Properties

A MD is a running total of the quantity of matl can show

surplus or deficient

• Excavation = ascending MD curve – between stn A&B, and between D & E

• Filling =decending MD curve – between B & D

• Volume of cut/fill can be calculated by a projection ofthe mass diagram line pts to the vertical scale

• Maximum or minimum pts on the MD = a change from

excavation to filling or vice versa at pts B and D

• When MD curve crosses the Datum Line (zero

volume) at C, no excess or deficit of matl at pt C

• At Stn E = waste situation, excess matl will have to be

hauled to dumping site

Characteristic of Mass Haul Diagram ref Shrivastava


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Characteristic of Mass-Haul Diagram – ref Shrivastava pg 145

• Mass haul curve represents the algebraic summation of the qty

of earthwork in the direction in which the chainage of the

station progresses

• If the algebraic summation (or cumulative volume) is plus it

indicates the cutting and is plotted upwards. If minus, it

indicates the filling and is plotted downwards, with reference to

base line

• The slope of the mass-haul curve changes with the volume

between station. If the curve is ascending, it indicates

excavation or cut. Decending curve indicate embankment or

fill.• The lowest point of a loop that form a sag, it occurs at the end

of the fill. The highest point of a loop that form peak, it occurs

at the end of the cut

Characteristic of Mass Haul Diagram ref Shrivastava


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Characteristic of Mass-Haul Diagram – ref Shrivastava pg 145 -continue

• The vertical distance between a valley point and the next

forward ridge point gives the total volume of the cut. And the

vertical distance between a ridge point and the next forward

valley point gives the total volume of the fill.

• Between any 2 consecutive pts where a horizontal line or base

line intersects the mass haul curve, the qty of earthwork is

balanced.

• If the loop of the mass-haul curve is above the balance line,

the excavated matl is to be moved in the direction in which the

station progresses or from left to the right in the MHD. Where

the loop is below the base line, the excavated matl is to bemoved in the opposite direction or from right to left

• The maximum ordinate of any loop represent the total qty of

earthwork that is to be moved from cut to fill


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Using Mass Diagram

• MD is an analysis tool for selecting appropriate equipment for excavating

and hauling matl

• Analysis using balance lines & calculating avg hauls

Balance lines:

• Horizontal line of specific length that intersects the MD in 2 places

• Can be constructed so that its length is the maximum haul distance for diff

type of equipment• Max haul distance the limiting economical haul distance for a particular

equipment (mc) – use to fix location for mc

• Ref- Table 3.2 pg 77

Machines Type Economical Haul Distance

Large dozer- pushing matl Up to 90m (300 ft)

Scrapers 90 to 1500m (300-5000ft)

Loader & Trucks Haul greater than 1500m


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Balance lines: - continue..

• Fig 2.7 shown a balance line AC

• For a large push-loader scraper, the distance between stns A

and C= 1500m (5000 ft) ref Table 2.2

• Between the ends of the balance in (A and C), at C the cut

volume = fill volume

• Between stn A and C, the amount of matl the scrapers will

haul = the vertical scale =‘Q’

• The avg haul the multiple balance lines and the area shown

is a rectangular.

• The avg haul distance = the length of a horizontal line placed

1/3 of the distance from balance line in the direction of thehigh or low pt of the curve

• It is when the general shape of the MD is a triangle ( 2

triangles)

Fi 3 14 ( 8) MD i h b l li


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Figure 3.14 (pg78) – MD with a balance line

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B l li ti


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Balance lines: - continue..

Ref Fig 3.15 pg 79 – multiple balance lines

• Avg haul for an equipment, where distance = midway between balance

lines

• When the curve is above the balance line – direction of haul is from left to

right i.e up stationing

• When the curve is below the balance line – direction of haul is from right to

left i.e down stationing

• Length of the balance line = max or min haul distances for the balancedearthmoving operation - to conform to capabilities of equipment to be

utilised

• Equipment/mc to operate at haul distances within its range of efficiency

• In fig 2.8, dozers will be used to push the short haul matl.

• Using dozers the excavation between stns C and D will be placed betweenstns D and E

• Using a scraper – to excavate matl between stn A and C & haul to fill

between stns E and G

Note: In Fig 2.8, yardage= volume in yd3 or for us to use m3

Figure 3 15 – 2 balance lines of a MD


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Figure 3.15 – 2 balance lines of a MD

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igure 3.14 – Using MD & Profile to determine avg haul grades


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g g g g

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1/2h

1/2h

Average Grade:


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Average Grade:• When the MD & the project profile are plotted one on top of the

other, ref Fig 3.14. and Fig 3.15 , the avg haul grades of the

earthmoving operation can be approximated• On profile view, draw a horizontal line that divide the cut area

in half in vertical dimension. Do the same to fill area.

• The diff in elevation between these 2 lines provide the vertical

distance to use in calculating the avg grade for the haulinvolving the matl in the balance

• Avg grade % = (Change in elevation/Avg haul distance) x 100

• Ref Fig 3.14 - The avg grade from the cut to the fill

• = (-18 ft/203)x100 = -8.9%• The return trip will be up a 8.9% grade

(involve transport cost)


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Haul Distances: continue


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Haul Distances: ….continue

Ref Table 3.3 Table 3.3 Earthwork Vol For MD.xls

• Column 12 - lowest pt of the valley = -28,539 at Stn 5 +00

- high pt of -17,080 at Stn 8+ 00- 2nd lowest pt = -22,670 at Stn 10 +00

Sum of values of of the peak and low pts = total excavation to

be moved longitudinally,

b =[(28,539 – 17,080) + (22,670-17,080) + (17,080-0) =33,188 yd3]

• Haul 1 = 11,459 yd3

• Haul 2 = 5,590 yd3

• Haul 3 = 17,080 yd3

Ref Fig 3.17

Calculating Haul Distances: Ref MD

http://localhost/var/www/apps/conversion/tmp/scratch_3/Table%202.3%20Earthwork%20Vol%20For%20MD.xlshttp://localhost/var/www/apps/conversion/tmp/scratch_3/Table%202.3%20Earthwork%20Vol%20For%20MD.xls


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Calculating Haul Distances: Ref MD

Avg haul distance for any individual haul,

= area enclosed by the balance line and zero datum / amount of

matl hauled

Graphically = the vertical mid point of the area

= Area from 0 +00 to 15+ 00h0 =0, h1= 3631, h2=13,641....h13=17080, h14= 8502, h15=0

= 213,654 stn-yrd

Avg haul distance= 213,654/17,080 =12.51 stn

Graphically = 12,200 ft

SBC2253_OCW_Mass_Haul_Diagrams.pdf

Fig 3 17 Mass Diagram – plotted from data Table 3 3

http://localhost/var/www/apps/conversion/tmp/scratch_3/SBC2253_OCW_Mass_Haul_Diagrams.pdfhttp://localhost/var/www/apps/conversion/tmp/scratch_3/SBC2253_OCW_Mass_Haul_Diagrams.pdf


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Fig 3.17 Mass Diagram – plotted from data Table 3.3

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Haul 1Haul 2

Haul 3

28,539

17,080

22,670


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lecture 3a-earthwork & ms diagram 2

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