Planning for Earth

work Construction

Gladys Anabel 1806227774

Adesha Novrima 1806227660
Radifan Halif 1806227856
 OVERVIEW

1 Preparation for
Earthwork Construction

2 Dozers

3 Scrapers
2
PART 1
Planning for Earth Work Constructions
 Earthwork is the process that involving excavate,
transported and compacted the surface of the earth
at a location.

There are four main process in earthwork that is

excavation, transportation, unloading and
compaction.
4
Nuriqram, Muhammad. https://www.scribd.com/doc/227665931/earthwork-in-construction-site
Planning is important for:
Knowing the objectives and requirements

Defining work elements

Developing safety

Improving efficiency

Creating accurate schedules

Respond for future change

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Performance on construction
work depends on

The quantities involved

The haul distances
The work hazards
The various constraints

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 SAFETY

Bureau of over 7600 deaths between 1992 and 2010 at

Labor a rate of about 404 deaths annually due to
Statistics mobile heavy machinery

Bureau of Crane collapses caused 25 deaths and 59

Labor injuries, and contact with crane load caused
Statistics 6 deaths and 10 injuries

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 SAFETY

Safety Planning
Deciding actions need to be
All equipment entail risk Assessment of risk
taken

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 EARTHWORK PLANNING

Quantity Survey Mass Excavation

Structural
Excavation

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Graphical Presentation of Earthwork (1)

Plan View

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Graphical Presentation of Earthwork (2)

Profile View

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Graphical Presentation of Earthwork (3)

Cross Section View

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 Earthwork Quantities

End-Area Determination
To see the cross section
of area

- Digitizing tablet
- Planimeter
- Trapezoidal
Computations

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 Earthwork Quantities

Average End Area

To determine the volume
bounded by two cross
sections or end areas

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 STRIPPING

Source: https://www.youtube.com/watch?v=c_KZILJ-HKg 15
Net Volume

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Mass Diagram

- Quantities of materials
- Average haul distance
- Types of equipments
that should be
considered

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ECONOMIC HAUL DISTANCE

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PART 2
Dozers
 Dozers are machines designed primarily for cutting and pushing
material (soil, sand, rubble, or other such) during construction
work.

Provide durable tractive power with mobility and speed

.
Dozers: An Intro

Dozers are classified on the basis of its running gear:

Wheel-type dozers Crawler type dozers

(tracklaying) 20
WHEEL DOZERS VS CRAWLER DOZERS
Wheel Dozers Crawler Dozers

Good on firm soils, concrete and - Can work on variety of soils

abrasive soils (that have no sharp-edges - Sharp-edged pieces is not as
pieces destructive to dozers, though fine sand
will increase running gear wear

Best for level or downhill work Can operate up to 45 degree steep slope
Wet weather (causing soft and slick Can work on soft ground and mud-slick
surface condition) can slow and stop the surfaces
operation

Fast return speed (8-26 mph) Slow return speed (5-10 mph)

Only moderate blade loads Can push large blade loads

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Performance of work: Traction
Tracklaying machines

continuous tracks of linked shoes that moves

in the horizontal plane across a fixed rollers

Linked shoes made of heat-treated steel

designed to resist water and abrasion.

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Traction requirement in
Crawler Dozer

Proper undercarriage (tire selection)

Standard crawler dozer appropriate for rock to moderate

soft ground

● Standard:: Ground pressure of 6-9 psi (41-62 kPa)

● LGP (Low-ground pressure): undercarriage
configuration for soft soil 3-4 psi (21-28 kPa)
● Extralong (XL): finishing work of specification

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Wheel-type Dozers
Wider tires Greater contact area compacted

Attain higher Loss of pulling effort

speed

Low coefficient
of traction Slip its wheels when developing its
rubber tires with pulling effort
ground surfaces

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Dozers: How it’s powered

Rated by flywheel power: efficiently store rotational kinetic energy

Internal Combustion: Gasoline Engines for Electric and air-powered

Diesel engines smaller machine for tunnelwork

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Transmission as the ability to provide speed power ratio

Torque converter and power shift

Direct drive transmission
● Transmitted straight through the ● Shifting transmission as power shift
transmission as single shaft (highest ● Providing efficient flow of power
gear) from the engine to the tracks giving
● Direct-drive will be superior when superior performance involving
work involving constant load variable load
condition (where full blade loads
must be pushed long distance)

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Performance chart of power shift

200-hp 45,560 lb track type dozer 216-hp 45,370 lb wheel dozer

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COMPARISON OF PERFORMANCE

200-hp 45,560 lb track type dozer 216-hp 45,370 lb wheel dozer

Coefficient of traction factor in dry clay loam

Rubber tires 0.50-0.70
Track 0.90

Drawbar pull:
Track-type found to be
45,560 x 0.90 = 41,004 lb Therefore a wheel-type dozer must
be heavier as 50% than a
Wheel-type dozer considered track-type dozer to develop the
45,370 x 0.60 = 27,222 lb same amount of usable force

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Dozers and its purposes
1. Clear the site of work
2. Make the land level
3. Prepare pilot roads through mountains and hard
grounds
4. Excavate material and haul for a distance of about 100
meters
5. Spreading earth
6. Backfilling trenches
7. Maintaining haul roads

Size of a bulldozer Dimensions of the blade Condition under which it

operates

● Efficiency of operator
● Nature of soil
● Topography of area
● Type of weather condition
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Dozer: Project Employment

➔ Stripping
Removal of thin layer of covering material (mostly top soil)
➔ Backfilling
Replacing or reusing the soil used for construction
➔ Spreading
Spreading process of material duped by trucks or scrapers
➔ Slot Dozing
Cut through sidewalls

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Blades of a Dozer
Consist of moldboard with replaceable cutting edges
and side bits. Connected to a dozer

Push arm & tilt cylinders C-frame

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Tilt Pitch Angling

Permits concentration of Pivotal movement of the Pushing material to

the driving power to the joint between the dozer one of the side of the
portion of length and the blade. Increasing blade (rolling it to the
the angle of cutting edge side) or side casting
attack

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Blade Performance

Horsepower per foot (hp/ft) Indicator of the blade’s ability to

penetrate and obtain a load.

Straight Blades
● Backfilling, grading and spreadfilling material
● Fixed position perpendicular to the dozer’s line of travel
● Have the ability to pitch (to pry on hard material)

Angle blades
● Wider in facelength by 1 to 2 ft than S blade (can angled up
to 25 degree)
● Side-casting material: backfilling or making sidehill cuts

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Universal Blade
● Wider than S blade and edges canted
forward about 25 degree
● The canting reduce spillage of loose
material making it efficient moving large
loads over long distances

Semi-U blades
● Combination of S and U-blade design.
● Increase the capacity of load

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Cushion Blade
● Used for push-loading scrapers
● The short length helps maneuvering into position
behind the scrapers

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Dozer Production Estimating Format
The factors that control dozer production rates
1. Blade Type
2. Type and condition of material
3. Cycle Time: sum of the time required to push a load, back-track,
maneuver into position to push again

CATERPILLAR D7G CRAWLER DOZER WITH STRAIGHT BLADE for

slot-dozing operation. Material of dry, noncohesive silty sand to be moved
distance of 300 ft. dozing on a downhill of 10% grade. Operator will have
power-shift transmission, material weights of 108 pcf (lb/cf) and
estiamted to swell 12%.

Job efficiency of 50-min hour with an average skill operator and visibility
& traction should be satisfactory
Clalculate the direct cost assuming O&O cost for the dozer is $32.50/hour
and operator’s wage of $14.85 per hour.
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Step 1
Ideal Maximum Production
Determining the ideal maximum production based on the dozer model and
type of blade

D7G with straight blade ideal

production for 300 ft push is
170 lcy

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 Step 2: Material-Weight Correction Factor

Bank weight for this project material is given as 108 pcf

Therefore,
108 pcf x 27 cf/cy = 2,916 lb/bcy

With swell of 12%, therefore,

2,916/1.12 = 2,604 lb/lcy

2,300 lb/lcy (from table)

Thus material weight

correction to be

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Step 3: Operator Correction Factor
Average skill 0.75

Step 4: Material-Type Correction Factor

Dry, noncohesive : 0.80

Step 5: Operating-Technique CF
Slot Dozing : 1.20

Step 6: Visibility Correction Factor

Good visibility, use 1.00

Step 7: Efficiency Factor

50 min-hour : 0.83

Step 8: Machine Transmission Factor

Power-shift tractor : 1.00

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Step 9: Blade Adjustment Factor

Straight Blade : 1.00

Step 10: Grade Correction Factor

(-) Favorable
(+) Unfavorable

Grade (-10% grade) : 1.20

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Step 11: Product of the Correction Factors

= 0.88 x 0.75 x 0.80 x 1.20 x 1.0 x 0.83 x 1.0 x 1.0 x 1.24

= 0.652

Step 12: Dozer Production

170 lcy/hr x 0.652 = 111 lcy/hr

Step 13: Material Conversion unit

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Dozer Safety

OHSA Construction Standards specifies many safety rules. Section 1926.602(a)(2)(i) specifically
stated that

“Seatbelts shall be provided on all equipment covered by this section and shall meet the
requirements of the Society of Automotive Engineers, Seat Belts for Construction
Equipment”

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PART 3
Scrapers
Scraper, in engineering, is machine for moving earth
over short distances over relatively smooth
areas.Either self-propelled or towed, it consists of a
wagon with a gate having a bladed bottom.

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HOW?
Bowl with Bowl is The Blade Cut
Bladed Bottom Lowered into the soil

The Bowl is
Transport and The Bowl filled
raised and
Unloading with soil
closed

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SCRAPER OPERATION
● Bowl - Loading and Carrying Component of Scraper
● Apron - The front wall of the bowl, enabling material
flow into the bowl
● Ejector - Rear Vertical Wall of the Bowl, Pushing
Mateial for Spreading.

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SCRAPER TYPES:
Pusher - Loaded
● Single - Powered Axle
● Tandem - Powered Axle

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Self - Loading
● Push - Pull, Tandem Powered Axles
● Elevating
● Auger

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Volume or Capacity of a Scraper
● Expressed in Cubic Yards Bank Measure (bcy)
● Approximated by multiplying the loose volume in
the scraper to a swell factor.

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HOW IS IT PERFORM?

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Scrapper Production Cycle
Loading - Haul Travel - Dumping and Spreading - Turning -
Return Travel - Turning and Positioning to Pick Up Another
Load

Total Time = Load + Haul + Dump + Turn + Return + Turn

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Scraper Production Estimating
Format

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Scraper Production Estimating Format (CAT 631E Scraper)

Step 1 ( Weight)
Determine:
● Empty Vehicle Weight (EVW) - From manufacturer data
● Load Weight - Load Volume and Unit Weight of Material
● Gross Vehicle Weight (GVW) - Sum of EVW and Load Weight

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Step 2 (Rolling Resistance)
● A well maintained haul road enable faster travel speeds and
reduces the cost of scraper maintenance and repair.
● A well maintained haul road will also reduce the haul travel
time which reduced production loss.

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Step 3 (Grade Resistance/Assistance)
Is Usually a function of the project topography. From
where and to the material must be excavated ot hauled. Can
be expressed in pounds per ton of vehicle weight or
percentage.

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Step 4 (Total Resistance/Assistance)
Sum of Rolling Resistance (RR) and Grade Resistance (GR)

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Step 5 (Travel Speed)
Can be determined from manufacturer prefomance,
retarder charts, or project condition.

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Step 6 (Travel Time)
Sum of the times scrapers requires to transverse each
segment of the haul and return routes.

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Step 7 (Load Time)
Load Time is a management decision that should be made
after careful evaluation of the production and cost effects.

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Rates of Production is also vary with different rates of loading
times:

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Step 8 (Dump Time)
Dumping Time Vary with Scraper Types.

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Step 9 (Turning Time)
Greatly affected by the type and size of scrapers.

Step 10 (Total Cycle Time)

The sum of the time that has been examined in previous
steps.

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Step 11 (Pusher Cycle Time)
Used when a push tractor was used during the Operation.

Step 12 (Balance Fleet)

The number of scrapper a push tractor can serve

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Step 13 (Efficiency)
Account for actual productive operation.
Step 14 (Production)
If the scrappers number is less than balance number,
scrapers will control production and tractor will idle.
Step 15 (Cost)
Faster Project Schedule means more scrapers and equals
to more cost.
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SCRAPER SAFETY
Never Operate at Unsafe speed and Always wear seatbelts.

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REFERENCE LIST

Peurifoy, Robert L., Schexnayder, Clifford J., and Shapira, Aviad. (2006). Construction Planning,
Equipment, and Methods, Seventh Edition. New York: McGraw Hill.

Smiley, Seth. (2017). Common Injuries Caused by Heavy Equipment, Smiley [online]. Available
from:
https://www.smileyfirm.com/common-injuries-caused-heavy-equipment/ (Accessed 14
February 2020)

The Editors of Encyclopaedia Britannica. “Scraper.” Encyclopædia Britannica, Encyclopædia

Britannica, Inc., 11 Apr. 2016, www.britannica.com/technology/scraper-construction. (Accessed on
17 February 2020)

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