L1 Planning for Earthwork Construction

L1L1CCE 4204

Planning for Earthwork ConstructionEvery construction project is a unique undertaking. Therefore, planning is undertaken undertaking. Therefore, planning is undertaken to understand the problems and to develop courses of action.

Planning Understand project objectives and requirements Define work elements Develop safe construction methods and avoid hazards

Improve efficiency Improve efficiency Coordinate and integrate activities Develop accurate schedules Respond to future changes Provide a yardstick for monitoring and controlling execution of project activities

Planning Earthwork Construction Review the Contract Documents Study the plans Plan the Work Perform quantity take-off Determine costs

Variables related to the work: The quantities involved, basically volume or weight The haul distances The grades for all segments of the hauls

The work hazards The work hazards Various contractual and legal restraints

Typical constraints: Contract requirements described in the drawings and technical specifications, completion dates, etc. Legal requirements (OSHA, licensing, environmental control)control) Physical and/or environmental limits of the job

Fabrication and material storage Sequencing of construction operations (traffic control) Climatic conditions that limit when certain activities can be performed, such as paving or stabilization

Planning Earthwork ConstructionA site visit is strongly recommended to relate the physical site characteristics to the work details.

Safety In 2002 there were 1,181 highway construction work zone fatalities in the United States Safety should be a part of all construction planning

Earthwork Planning Quantity Survey The process of calculating the quantity of materials required to build a project Mass Excavation The requirement to excavate Mass Excavation The requirement to excavate substantial volumes of material, usually at considerable depth or over a large area Structural Excavation Excavation undertaken in support of structural element construction, usually involves removing materials from a limited area

Planning Earthwork ConstructionVisit the site examine the material; does it match what the lab reports say?match what the lab reports say?

Graphical Presentation of Earthwork Plan View A construction drawing representing the horizontal alignment of the work Profile view A construction drawing depicting a vertical plane cut through the centerline of the workvertical plane cut through the centerline of the work Cross Section View A construction drawing depicting a vertical section of earthwork at right angles to the centerline of the work Cross Sections Earthwork drawings created by combining the project design with field measurements of existing conditions

Plan View (looking down from above)

Station Number

Profile View (looking from side)New roadelevations shown as solid linesas solid linesExisting elevationsshown as dashed lines

Cross Section View (looking at a section thru the road)

Cross Sections Existing Elevations Shown as Dashed LinesProposed Elevations Shown as Solid Lines

Earthwork Quantities End-Area Determination

Digitizing Tablet Planimeter Trapezoidal Computations A2 2’ Trapezoidal Computations

Average End AreaVolume = (A1 + A2) X L

2 27

A1

A2

2’2

1

2 1

3’

2’

2’100 ft

Stripping The upper layer of organic material that must be removed before beginning an excavation or embankment

Net Volume The volumes from fill cross sections represent Compacted volume, expressed as Compacted Cubic Yards (ccy) The volume of cut sections represent in situ volume, the volume in its natural state is expressed as Bank Cubic Yards (bcy) If cut and fill volumes are to be combined, they must be converted into compatible volumes

Net Volume Bank cubic yards (bcy) Loose cubic yards (lcy) Compacted cubic yards (ccy)

bcy lcy ccy

Earthwork Volume Sheet

Mass Diagram Cumulative Quantities of materials Average haul distances Indicates the types of equipment that should be considered for accomplishing the workconsidered for accomplishing the work

Properties of a Mass Diagram

MASS DIAGRAM

0

500

1000 Embankment requirements exceeds excavation quantity.-500

- 1000

0 + 00 1 + 00 2 + 00 3 + 00 4 +00 5 + 00 6 + 00

Descending lines

MASS DIAGRAM

0

500

1000

Ascending lines-500

- 1000

0 + 00 1 + 00 2 + 00 3 + 00 4 +00 5 + 00 6 + 00

Excavation exceeds embankment requirements

MASS DIAGRAM

0

500

1000 Maximum and minimum points

-500

- 1000

0 + 00 1 + 00 2 + 00 3 + 00 4 +00 5 + 00 6 + 00

Transition point

Using the Mass Diagram Balance Lines A horizontal line of specific length that intersects the mass diagram in two places1000

0

-500-1000

500

1000

1+00 2+00 3+00 4+00 5+00 6+00 7+00 8+00

VOLUME

CCY

STATIONS

FILL CUT

CUT FILL

Mass Diagram with a Balance Line

MASS DIAGRAM

0

500

1000

Zero balance line-500

- 1000

0 + 00 1 + 00 2 + 00 3 + 00 4 +00 5 + 00 6 + 00

Excavation quantity equals embankment requirement..

Economical Haul Distances

Average Grade

Average Grade Percent = Change in Elevation * 100

Grade affects equipment efficiency and production rates.

Average Grade Percent = Change in Elevation * 100Average Haul Distance

May be estimated from the profile view.

Two Balance Lines on a Mass DiagramNote that opposingpoints are in balance.points are in balance.Total cut = total fillFrom point to point.

Spread Production Spread A group (or crew) of construction machines that work together to accomplish a specific construction task such as excavating, hauling, and compacting materialcompacting material

Three Link Earthwork System

Pricing Earthwork Operations The cost of earthwork operations will vary with the kind of soil or rock encountered and the methods used to excavate, haul, and place the material in its final deposition It is usually not too difficult to compute the volume of earth or rock to be movedbe moved Estimating the cost of actually performing the work depends on both a careful study of the project plans and a diligent site investigation

How much material must be moved?What equipment is required? And daily cost of the equipment?What is the estimated daily production of the crew?

AGTEK is one of the leading software tools for managing earthwork.See: http://www.agtek.com/

Mobile Heavy Equipment Simulator

Mobile Heavy Equipment Simulator

Motor grader Cab