LECTURE 5
LOADING & HAULING
Sung-Woo MOON, Ph.D, P.E
September 24 , 2018
Nazarbayev University
Department of Civil Engineering
Lecture 05
ECE 404: Construction Technologies & Processes 2
Crawler dozer
Wheel dozer
BULLDOZERS
Lecture 05
ECE 404: Construction Technologies & Processes 3
•A tractor unit equipped with a front-mounted earthmoving blade
•The blade is used to push, shear, cut, and roll material ahead of
the tractor
•Self-contained units that are designed to provide tractive power for
drawbar work
•The larger the difference between the line-of-force transmission
from the machine and the line of resisting force the less effective
the utilization of developed power
BULLDOZERS
Lecture 05
ECE 404: Construction Technologies & Processes 4
•Parts of dozer
BULLDOZERS
COMPONENTS
Lecture 05
ECE 404: Construction Technologies & Processes 5
•Crawler (track laying) Tractor
BULLDOZERS
TYPES OF BULLDOZERS
•Wheel Type Tractor
–Single-axle
–Two-axle
•Single -axle drive
•Two-axle drive
Lecture 05
ECE 404: Construction Technologies & Processes 6
•Crawler BULLDOZERS (tractors)
–Operate on steeper side slopes and climb greater grades than
can wheel BULLDOZERS
–Suited for use in rough terrain or areas of low trafficability
because of their excellent traction and low ground pressure
(typically 6 to 9 lb/in2; 0.4 to 0.6 bar)
–Low-ground-pressure models with extra-wide tracks are
available having ground pressures as low as 3 lb/in2 (0.2 bar)
–Be equipped with attachments other than dozer blades
•Rakes : used for gathering up brush and small fallen trees
•Plows, rippers, and scarifires : used to break up hard surfaces
1 Bar = 100 kPa = 1×105 N/m2= 14.5 psi
BULLDOZERS
TYPES OF BULLDOZERS
•Crawler dozers (tractors)
–Suitable for jobs that require high tractive effort
–Rated by size and weight
DOZERS
TYPES OF DOZERS
