2. • General
Mechanization is the process of shifting from working
largely or exclusively by hand to do that work using
machines. Construction projects are becoming more
demanding and complicated in construction and delay
of projects would arise if conventional construction
method is used. Delays in construction are costly and
have prompted developers to embrace mechanization.
Construction machineries are used in order to achieve
larger output, cost-effective, execution of work that is
not feasible by manual efforts, reduce the amount of
heavy manual work which would cause fatigue,
maintaining large output, and finalize projects on time.
3. • Motivations for Mechanization of Construction Industry
• The work can be done speedily which avoid time and cost
over-runs.
• Large quantity of materials can be handled, so the size of
the project can be increased
• The complex projects involving high grade material.
• High quality standards can be maintained.
• Time schedule can be kept.
• Optimum use of material, man power and finance.
• Shortage of skilled and efficient man power.
• To control on the duration and cost implications by using
mechanized equipment over the Conventional method,
which can be used in the planning of construction
project.
4. • Lower insurance costs for builders.
• Easier and safer work for construction workers.
• Increased sustainability over a building’s lifetime.
• Little to no building-site construction waste.
5. • Earth Excavators
Excavators are heavy equipment consisting of a
boom, bucket and cab on a rotating platform known
as the control room. The house sits atop an under
carriage with tracks or wheels. All movement and
functions of the excavator are accomplished
through the use of hydraulic fluid, be it with rams or
motors.
6. • Types of excavator:
• Compact excavator
• Crawler excavator
• Wheeled excavators
• Backhoe loader
• Dragline excavator
• Long reach excavator
• Power shovel
• Suction excavator
7. • Excavators are used in many ways:
• Digging of trenches, holes and foundations
• Material handling
• Brush cutting with hydraulic attachments
• Forestry work
• Demolition
• General grading/landscaping
• Heavy lift, e.g. lifting and placing of pipes
• Mining, especially, but not only open-pit mining
• River dredging
• Driving piles, in conjunction with a Pile Driver
8. 1. Compact Excavator
A compact or mini excavator is tracked or wheeled vehicle
with an approximate operating weight from 0.7 to 7.5 tons.
It generally includes a standard backfill blade and features
independent boom swing. Hydraulic Excavators are
somewhat different from other construction equipment in
that all movement and functions of the machine are
accomplished through the transfer of hydraulic fluid. The
compact excavator's work group and blade are activated by
hydraulic fluid acting upon hydraulic cylinders. The
excavator's slew (rotation) and travel functions are also
activated by hydraulic fluid powering hydraulic motors.
9.
10. 2. Crawler Excavator
a) Mini-Crawler Excavator
With a wide range of available sizes and features like Power
Tech engines, zero-tail-swing, offset boom, multiple
attachments and ultra comfortable operator stations,
there’s excavator to fit every job. Hydraulic management
system, which helps by balancing hydraulic pressure and
flow and sensing when extra power is needed without
draining other systems.
11.
12. b) Heavy Crawler Excavator
Crawler excavator gets the job done with muscle,
control and peerless productivity. Efficient, cool-
running engines and enhanced hydraulics make
these the most-reliable and hardest-working
excavators yet. Climb into one of these best-in-class
cabs and unleash a mighty workhorse to tackle
toughest jobs.
13.
14. 3. Wheeled Excavators
Wheeled excavators easily navigate streets and hard
surfaces to deliver powerful bucket forces in well-
balanced, high-stability machines. Even with all that
muscle outside, operators find quiet comfort inside
spacious air conditioned cabs. Low effort levers
deliver smooth boom and bucket control.
15.
16. 4. Backhoe loader
Backhoe loader, also called a loader backhoe and
commonly shortened to backhoe, is a heavy
equipment vehicle that consists of a tractor fitted
with a shovel/bucket on the front and a small
backhoe on the back. Due to its relatively small size
and versatility, backhoe loaders are very common in
urban engineering and small construction projects
(such as building a small house, fixing urban roads,
etc).
17. Backhoe loaders deliver versatility and power in a cost-
efficient package, whether placing pipe, busting up blacktop or
digging deep. Each model features excavator-style boom,
bucket and hydraulics. Crowd power, swing torque and boom
and dipper stick lift are impressive and high pressure
hydraulics are powerful and quick. Easy-to-operate controls
smoothly blend functions.
18.
19. By comparing various types of machines for
excavation, for example, power shovels are
generally found to be the most suitable for
excavating from a level surface and for attacking an
existing digging surface or one created by the
power shovel; furthermore, they have the
capability of placing the excavated material directly
onto the haulers. Another alternative is to use
bulldozers for excavation.
20. The choice of the type and size of haulers is based on the
consideration that the number of haulers selected must be
capable of disposing of the excavated materials
expeditiously. Factors which affect this selection include:
• Output of excavators: The size and characteristics of the
excavators selected will determine the output volume
excavated per day.
• Distance to dump site: Sometimes part of the excavated
materials may be piled up in a corner at the job-site for
use as backfill.
• Probable average speed: The average speed of the
haulers to and from the dumping site will determine the
cycle time for each hauling trip.
21. • Volume of excavated materials: The volume of
excavated materials including the part to be piled
up should be hauled away as soon as possible.
• Spatial and weight constraints: The size and
weight of the haulers must be feasible at the job
site and over the route from the construction site
to the dumping area.
Dump trucks are usually used as haulers for
excavated materials as they can move freely with
relatively high speeds on city streets as well as on
highways.
22. The cycle capacity C of a piece of equipment is
defined as the number of output units per cycle of
operation under standard work conditions. The
capacity is a function of the output units used in
the measurement as well as the size of the
equipment and the material to be processed. The
cycle time T refers to units of time per cycle of
operation. The standard production rate R of a
piece of construction equipment is defined as the
number of output units per unit time. Hence:
23. The daily standard production rate Pe of an
excavator can be obtained by multiplying its
standard production rate Re by the number of
operating hours He per day. Thus:
……. (1)
……. (2)
……. (3)
where Ce and Te are cycle capacity (in units of
volume) and cycle time (in hours) of the excavator
respectively.
24. In determining the daily standard production
rate of a hauler, it is necessary to determine first
the cycle time from the distance D to a dump site
and the average speed S of the hauler. Let Tt be
the travel time for the round trip to the dump site,
To be the loading time and Td be the dumping time.
Then the travel time for the round trip is given by:
…. (4)
25. For a given dumping time Td, the cycle time Th of
the hauler is given by:
……. (5)
The daily standard production rate Ph of a hauler can be
obtained by multiplying its standard production rate
Rh by the number of operating hours Hh per day. Hence:
……. (6)
26. This expression assumes that haulers begin loading as
soon as they return from the dump site.
The number of haulers required is also of interest. Let
w denote the swell factor of the soil such that
wPe denotes the daily volume of loose excavated
materials resulting from the excavation volume Pe.
Then the approximate number of haulers required to
dispose of the excavated materials is given by:
……… (7)
