CE403 Construction Methodology

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CE403Construction Methodology

• Earthwork
• Volume Calculations

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Three Views Presented in Contract Documents to
Show Earthwork Construction Features

• Plan View

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Three Views Presented in Contract Documents to
Show Earthwork Construction Features

• Profile View

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Three Views Presented in Contract Documents to
Show Earthwork Construction Features

• Cross Sections

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Earthwork Volume Calculations

• Cross Sectional Methods
• Trench Excavations
• Average End Method
• Plan Area Methods
• Four Corner Method

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Trench Excavations

• Volume Cross Sectional Area X Length of Trench
• Eg. Find the volume (bank measure) of excavation
  required for a trench 3 ft (0.92 m) wide, 6 ft
  (1.8m) deep, and 500 ft (152 m) long. Assume
  that the trench sides will be approximately
  vertical
• Solution
• X-section area 3x6 18 sf
• Volume 18x500/27 333 BCY

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Average End Method
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Reminder
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Average End Area Method Example
Calculate the area between two end areas, 100 ft
apart.
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Average End Method
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Average End Method
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Average End Method
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Average End Method
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Average End Area Example 2
Station End Area (sf) Distance (ft) Volume (cy)
15000 360
15100 10,200 100
15200 18,000 100
15300 23,500 100
15400 12,600 100
15500 5,940 100
15600 400 100
Total Volume
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Average End Area Example 2
From 15000 to 15100 volume
(1001/2(36010200))/27 19,556 CY From 15100
to 15200 volume (1001/2(1020018000))/27
52,222 CY From 15200 to 15300 volume
(1001/2(1800023500))/27 76,852 CY And so on
and so on.
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Average End Area Example 2
Station End Area (sf) Distance (ft) Volume (cy)
15000 360
15100 10,200 100 19,556
15200 18,000 100 52,222
15300 23,500 100 76,852
15400 12,600 100 66,852
15500 5,940 100 34,333
15600 400 100 11,741
Total Volume 261,556 cy
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Earthwork Volume Calculations

• Cross Sectional Methods
• Trench Excavations
• Average End Method
• Plan Area Methods
• Four Corner Method

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Four Corner Method
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Four Corner Method
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Four Corner Method
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Grid Method

• Volume is the area of grid multiplied by the
  difference between the existing and the proposed
  elevations.

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Grid Method
Volume by Layers
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Contour Method
UK Reservoir Finish Elevations Scale 1 40
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Contour Method
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Contour Method
UK Reservoir Finish Elevations Scale 1 40
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Mass Diagrams

• Shows two curves
• A continuous curve representing the profile of
  the existing grade.
• A continuous curve representing the accumulated
  volume of earthwork plotted against the linear
  profile of the roadway.
• Tells Us
• Quantities of Materials to cut and fill
• Average Haul Distances
• Types of Equipment that should be considered

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Mass Diagrams
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Mass Diagrams - Definitions

• Cut volume of excavation for a given cut
• Fill volume of material to be added to an
  existing terrain for a given fill
• Waste volume of material that is required to be
  hauled off site
• Borrow volume of material that is required to
  be brought on site.

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Mass Diagram
Cut
Borrow
Fill
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Mass Diagrams

• The vertical coordinate of the mass diagram
  corresponding to any location on the roadway
  profile represents the cumulative earthwork
  volume from the origin to that point.
• Within a cut, the curve rises from left to
  right.
• Within a fill, the curve falls from left
  to right.

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Mass Diagrams
Cut
Fill
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Mass Diagrams

• A peak on the curve represents a point where the
  earthwork changes from cut to fill.
• A valley (low point) on the curve represents a
  point where the earthwork changes from fill to
  cut.
• When a horizontal line intersects the curve at
  two or more points, the accumulated volumes at
  these points are equal.

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Mass Diagrams
Turning Points
Balanced Points
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Mass Diagrams

• The average length of haul for a balanced
  section.
• The location and amount of borrow and waste for
  the project.

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Mass Diagrams
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