Trucks and Hauling Equipment

Trucks and Hauling Equipments

CE 504 : Construction Methods & Equipments Prof. K. N. Satyanarayana IIT Madras 1

TRUCKS AND WAGONS • Up to 100m - dozer or loader 100m - 1000m - scraper >1000m - trucks • Also conveyors or trays may be used if more economical and large job. • Heavy duty rear dump truck most widely used • Most trucks may be operated over any haul road for which the surface is sufficiently firm and smooth on which the grades are not excessively steep. CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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TRUCKS AND WAGONS • Some units designated as off-highway trucks because their size and total loads are larger than permitted on highways. Used on large highways projects where economically justified. • Classified based on: 1. Size and type of engine 2. No of gears 3. Kind of drive-two wheel, four wheel, six wheel etc. CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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TRUCKS AND WAGONS

4. No of wheels and axles and arrangement of driving wheels. 5. Method of dumping load - rear dump, side dump. 6. Class of material handled - earth, rock etc. 7. Capacity, in tons or m3-struck or heaped

CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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An Off-Highway quarry truck CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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A rigid frame rear dump truck

CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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TRUCKS AND WAGONS

• Ease or difficultly of dumping will depend upon the shape of the body such as extent of sharp angles, corners, and the contour of the rear. • For wet clay and similar materials should be free of sharp angles and corners. • Dry sand and gravel will flow easily from almost any shape of body. • For quarry rock, bodies should be shallow with sloping side boards. CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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TRUCKS AND WAGONS

• Wagons are tractors equipped with earth moving semi trailers. Mostly used - Bottom dump wagons • When discharging the loads onto fills, can dump their loads while moving.Very useful for spreading load. • Because of limited openings, difficulties may be experienced in discharging such materials as wet, sticky clay, especially in large lumps. CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Determination of No. of Haul Units Required.

• Cycle time, Determine the components of the cycle time for the truck in the video

CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Determination of haul units required • Cycle time = Fixed time + Variable time Fixed time includes the following: -Spot -Load -Maneuver -dump Variable time includes - Haul & Return CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Determination of No. of Haul Units Required.

Fixed time elements of spot, maneuver and dump may be estimated by using the tables below: Spot, maneuver, and dump time for trucks and wagons

Favourable

Bottom dump

Rear dump

1.1

0.5

Average

1.6

1.1

Unfavourable

2.0

2.5

CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Determination of No. of Haul Units Required.

• Load time = No. of bucket loads * Excavator cycle time • No. of bucket Loads = Haul unit capacity / Loader production at 100% Efficiency

• 100% efficiency loading rate intended to ensure that an adequate no. of trucks is provided so that the excavator will not have to wait for a truck. • Excavator have been found to operate at near 100% efficiency when actually loading.x

CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Determination of No. of Haul Units Required.

• May use either back or loose measure, but should use the same for both numerator and denominator. • No. of haulers required(N) = Haul unit cycle time / Load time This is no.of trucks theoritically required to keep a loader fully occupied. • N should be rounded up to the next integer. • Although the above method gives, reasonable values for field use, the loader will have to wait for haul units at times because of variability. CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Productivity of hauling equipments • If more than theoretical required no. of trucks is supplied, no increase in system production will occur, since limited by excavator output. However, if less than the required no. of trucks is supplied, system output will be reduced. When the no. of trucks provided is less than N then Expected Production =

Actual No. of units

* Excavator production

N Precise value of N,not integer CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Determination of No. of Haul Units Required

• Important condition in selection of excavator / haul unit combination is effect of size of target the haul unit presents to the excavator operator. If target too small, excessive spillage.Hence cycle time is increased. • Rule of thumb: - For haul unit loaded by shovels, backhoes and loaders should have capacity of 2 to 5 times excavator bucket capacity. - Draglines and cliamshells require larger targets 5 to 10 times excavator bucket capacity. CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Determination of No. of Haul Units Required.

• Desirable to have haul units with integer no. of bucket loads. • Decrease swing angles to increase production. • Other technique to maximize production - If possible, stagger starting and quitting times so that bunching does not occur. - Avoid over loading. Excessive repair and maintenance. CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Determination of No. of Haul Units Required.

- Maintain haul roads in good condition - lesser RR, reduced travel time, & minimize equipment wear. - Develop efficient traffic pattern for loading, hauling and dumping. - Avoid speeding. - Provide stand by units.

CE 504 : Construction Methods & Equipments

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Example (Truck Productivity calculation) • Rear dump truck with specifications as follow are used to haul sandy clay. The performance charts shown is valid for these trucks. • Capacity – – – – –

Struck, 11. 2 cubic meter Heaped, 2:1, 14 cubic meter Net Weight empty = 16, 700 kg Pay Load = 20,000 kg Gross Vehicle weight = 36, 700

CE 504 : Construction Methods & Equipments

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Example Contd. Trucks will be loaded by a hydraulic hoe having a 2.3 cu m. bucket. The haul road from the borrow site to the fill is a 5km downhill grade of 1%. It is earth, poorly maintained. Dump time will average 2min because of expected congestion on the fill. The hoe should be able to cycle in 20 sec. The sandy clay has a loose unit weight of 1275kg/m3. A realistic efficiency estimate for this work is a 50-min hour. RR = 60kg/ton

CE 504 : Construction Methods & Equipments

Trucks and Hauling Equipments.

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Procedure • • • • • • • •

Step 1 : Number of bucket Loads Step 2: Load Time Step 3: Haul Time Step 4: Return Time Step 5: Dump Time Step 6: Total Cycle Time of the truck Step 7: Number of trucks required Step 8: Production CE 504 : Construction Methods & Equipments

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