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Construction equipment management chapter 3

Construction Equipment Management

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Construction equipment management chapter 3

1. 1. Madawalabu Madawalabu University University Construction Equipment and Plant Management COTM 4202
2. 2. General  Estimating and planning involves the judicious selection of equipment, the careful scheduling of time and resources, and the accurate determination of expected system output and cost. Definition  It is the number of units and the size of equipment that would permit the constructor to accomplish the activity with a duration resulting in the lowest cost. 2 February 2019 2 COTM 4202
4. 4.  Total power that an engine is capable of generating is expressed as its horsepower.  Available horsepower is power that is available to perform work after taking into account losses and consumption in other machine functions.  Rimpull is defined as the tractive force between the driving wheels and the surface on which they travel.( V is velocity in mph)  Total power that an engine is capable of generating is expressed as its horsepower.  Available horsepower is power that is available to perform work after taking into account losses and consumption in other machine functions.  Rimpull is defined as the tractive force between the driving wheels and the surface on which they travel.( V is velocity in mph) 2 February 2019 COTM 4202 4
5. 5. Power generated by engine 2 February 2019 COTM 4202 5 Drawbar Pull Rolling Resistance Rimpull
6. 6.  Rolling resistance is resistance offered to movement of materials on a plain surface; often expressed in pounds per ton of materials.  Rolling Resistance depends upon: 2 February 2019 COTM 4202 6
7. 7. 2 February 2019 COTM 4202 7
8. 8.  The force-opposing movement of a machine up a frictionless slope is grade resistance.  The effect of gravitational force in aiding movement of a vehicle down a slope is grade assistance. 2 February 2019 COTM 4202 8 F= 20 lbs/ G% per Ton
9. 9.  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 standard production rate R of a piece of construction equipment is defined as the number of output units per unit time.  The cycle time T refers to units of time per cycle of operation.  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 standard production rate R of a piece of construction equipment is defined as the number of output units per unit time.  The cycle time T refers to units of time per cycle of operation. 2 February 2019 COTM 4202 9
11. 11.  It is time for moving load from production site to disposal site. Longer time will reduce productivity.  To determine the productivity of a hauler, › Let: D be the distance from source to a dump site, S be the average speed of the hauler, Tt be the travel time for the round trip to the dump site, To be the loading time,Td be the dumping time plus other delays.  Then the travel time for the round trip is given by:  It is time for moving load from production site to disposal site. Longer time will reduce productivity.  To determine the productivity of a hauler, › Let: D be the distance from source to a dump site, S be the average speed of the hauler, Tt be the travel time for the round trip to the dump site, To be the loading time,Td be the dumping time plus other delays.  Then the travel time for the round trip is given by: 2 February 2019 COTM 4202 11
12. 12.  Human and machine system suffer from inherent delays due to reaction time and capacity, say Td. 2 February 2019 COTM 4202 12
13. 13.  For a given dumping time Td, the total cycle time Th of the hauler is the sum of loading time, travel time and damping time given by:  For a given dumping time Td, the total cycle time Th of the hauler is the sum of loading time, travel time and damping time given by: 2 February 2019 COTM 4202 13
14. 14.  Optimum number of haul units (N) is determined by:  NB: Rounding down will maximize haul unit productivity.  Optimum number of haul units (N) is determined by:  NB: Rounding down will maximize haul unit productivity. 2 February 2019 COTM 4202 14
15. 15.  An 16 cubic meter dump truck has a loading time of 3 min, a travel time of 7 min, and the dumping and delay times of 5 min. Calculate the cycle time of the hauler and optimum number of hauling units.  An 16 cubic meter dump truck has a loading time of 3 min, a travel time of 7 min, and the dumping and delay times of 5 min. Calculate the cycle time of the hauler and optimum number of hauling units. 2 February 2019 COTM 4202 15
16. 16.  The daily standard production rate Pe of an excavator is is given by:  He is the operating hours per day  Ce is the cycle capacity (in units of volume) of the excavator  Te is the cycle time (in hours) of the excavator  The daily standard production rate Pe of an excavator is is given by:  He is the operating hours per day  Ce is the cycle capacity (in units of volume) of the excavator  Te is the cycle time (in hours) of the excavator 2 February 2019 COTM 4202 16
17. 17.  The daily standard production rate Ph of a hauler is given by:  Rh is standard production rate  Hh is the number of operating hours per day  The daily standard production rate Ph of a hauler is given by:  Rh is standard production rate  Hh is the number of operating hours per day 2 February 2019 COTM 4202 17