TRUCKS AND HAULING EQUIPMENT

CONSTRUCTION EQUIPMENTS AND METHODS

By- VARUN Y.S.RACHANA AGUTALE

CONSTRUCTION TECHNOLOGY AND MANAGEMENTVNIT

TRUCKS

Trucks are hauling units that provide relatively low hauling costs because of their high travel speeds.

Trucks provide a high degree of flexibility permitting modifications in the total hauling capacity of a fleet and adjustments for changing haul distances.

Most trucks may be operated over any haul road for which the surface is sufficiently firm and smooth and on which the grades are not excessively steep.

Some trucks now in use are designated as off-highway trucks because their size and total load are larger than that permitted on public highways. These trucks are used for hauling materials on large project sites, where their size and costs are justified.

TRUCKS CLASSIFICATION

Trucks may be classified according to a number of factors including:

1. The method of dumping the load. a) Rear dump trucks

b) Bottom-dump Truck

c) Side-dump Truck

2. The size and type of engine-gasoline, diesel, butane or propane

3. The kind of drive-two wheel, four wheel or six wheel

4. The no. of wheels and axles, and the arrangement of driving wheels

5.The class of material hauled-earth, rock, coal or ore

6. The capacity-gravimetric (tons) or volumetric (cubic yards)

7. The type of frame- rigid frame or articulated

RIGID FRAME REAR DUMP TRUCKS They are suitable for use in hauling many types of materials.

The shape of the body, such as the extent of sharp angles & corners,& contour of the rear, through which the materials must flow during dumping, will affect the ease or difficulty of loading & dumping.

Continuous use under severe conditions requires a heavy-duty rock body made of high-tensile strength steel.

They can navigate grades of 20% for short distances.

ARTICULATED REAR-DUMP TRUCKS

They operate through high rolling resistance material and in

confined working locations.

The wheel drive, high clearance and low pressure radial tires combine to produce a truck capable of moving through soft or sticky ground.

They can operate on grades up to about 35%.

Most common are the 4x4 models but there are larger 6x6 models. They usually have high hydraulic system pressure (dumping cylinder hoists the bed faster) and the bed achieves a steeper dump angle.

CAPACITIES OF TRUCKS AND HAULING EQUIPMENT

Three methods of rating the capacities of trucks:

1) Gravimetric: the load it will carry, expressed as a weight.

2)Stuck volume: the volumetric amount it will carry, if the load is water level in the body.

3)Heaped volume: the volumetric amount it will carry, if the load is heaped on a 2:1 slope above the body.

TRUCK SIZE AFFECTS PRODUCTIVITYSmall Trucks

Advantages:

1. Maneuvering flexibility, which may be an advantage on restricted work sites.

2. Speed, can achieve higher haul and return speeds

3. Production, little impact if one truck breaks down

4. Balance of fleet, easy to match number of trucks to excavator production

Disadvantages of Small Trucks:

1.Number, more trucks increases operational dangers in the pit, along the haul road and at the dump.

2.More drivers required, more needed for a given output.

3. Loading impediment, small target for excavator bucket.

4. Positioning time, total spotting time greater because of the number required.

Large Trucks

Advantages:

1.Number, fewer needed for a given output.

2.Drivers required, fewer needed for a given output.

3. Loading advantage, larger target for the excavator bucket.

4. Positioning time, frequency of spotting trucks is reduced.

Disadvantages of Large Trucks

1.Cost of truck time at loading is greater, especially with small excavators.

2.Loads heavier, possible damage to the haul roads thus increasing the cost of maintenance of the haul road.

3. Balance of fleet, difficult to match no. of trucks to excavator production.

4.Size, may not be permitted to haul on highways.

Truck production Estimation

1) Number of bucket load:-

Balanced number of bucket load = Truck capacity/bucket capacity

2)Load time and Truck load volume:-

3) Haul Time:-

Haul time = haul distance haul speed

4)Return time:- Return Time = Return distance

Haul speed

5) Dump Time:- *Type of hauling unit *Congestion in the dump area

6) Truck cycle time

7) Number of trucks required:- =Truck cycle time

Excavator cycle time

8) Production:- = truck load*no of trucks*60min*Efficiency

Truck cycle time

Production Issues:-

1) Reach of the excavator2) Dumping height of the bucket3) Width of the bucket

Tyres:-1)Proper tyre size2)maintaining correct air pressure3)Based on resistance, which surface of the road offers to penetrationrigid road surface- small dia high pressureyielding road surfaces- large dia low pressure

TMPH(tonmilesperhour)=Avg tyre load x Avg speed during a day’s operation

Truck safety:-

1) Conduct hazard assessment of the work everyday, and ensure operators and drivers are aware of hazards2) Ensure berms are adequately built3) operator should follow all operating signals4) Use of spotter while backing with blind spot5) Should stay out of vehicle travel path6) wear high visibility safety clothing

THANK YOU