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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
  3. 3.  Haul unit horsepower  Haul road rolling resistance  Haul road grades  Haul unit loaded and empty weight  Haul unit transmission characteristics  Haul unit loading time  Haul unit travel time  Haul unit delay time  Altitude of the project site  Haul unit horsepower  Haul road rolling resistance  Haul road grades  Haul unit loaded and empty weight  Haul unit transmission characteristics  Haul unit loading time  Haul unit travel time  Haul unit delay time  Altitude of the project site 2 February 2019 COTM 4202 3
  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
  10. 10.  Time to load a mover for load shifting will determine loads that can be transferred. Longer loading time lesser will be productivity.  To is loading time  Te is cycle time for loader/excavator  Ch is capacity of a hauler (dump truck)  Ce loading rate/capacity of loader  Time to load a mover for load shifting will determine loads that can be transferred. Longer loading time lesser will be productivity.  To is loading time  Te is cycle time for loader/excavator  Ch is capacity of a hauler (dump truck)  Ce loading rate/capacity of loader 2 February 2019 COTM 4202 10
  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
  18. 18.  A 1.5 cubic meter front-end loader is going to load dump trucks with a capacity of 9.0 cubic meter. The loader takes 0.4 min to fill and load one bucket. The travel time in the haul is 4.0 min. Dump and delay times are 2.5 min combined. Calculate:  The loading time,  The cycle time of hauler,  Number of trucks,  The hourly production rate of haul units, and  The hourly production of loader  A 1.5 cubic meter front-end loader is going to load dump trucks with a capacity of 9.0 cubic meter. The loader takes 0.4 min to fill and load one bucket. The travel time in the haul is 4.0 min. Dump and delay times are 2.5 min combined. Calculate:  The loading time,  The cycle time of hauler,  Number of trucks,  The hourly production rate of haul units, and  The hourly production of loader 2 February 2019 COTM 4202 18
  19. 19.  A power shovel with a dipper of one cubic meter capacity has a standard operating cycle time of 30 seconds. Find the daily standard production rate of the shovel. Ce = 1 cu. mtr., Te = 30 sec. and He = 8 hours.  A power shovel with a dipper of one cubic meter capacity has a standard operating cycle time of 30 seconds. Find the daily standard production rate of the shovel. Ce = 1 cu. mtr., Te = 30 sec. and He = 8 hours. 2 February 2019 COTM 4202 19
  20. 20.  A dump truck with a capacity of 6 cubic meter is used to dispose of excavated materials at a dump site 4 km away. The average speed of the dump truck is 30 mph and the dumping time is 30 seconds. Find the daily standard production rate of the truck. If a fleet of dump trucks of 9 cubic meter capacity is used to dispose of the excavated materials for 8 hours per day, determine the number of trucks needed daily.  A dump truck with a capacity of 6 cubic meter is used to dispose of excavated materials at a dump site 4 km away. The average speed of the dump truck is 30 mph and the dumping time is 30 seconds. Find the daily standard production rate of the truck. If a fleet of dump trucks of 9 cubic meter capacity is used to dispose of the excavated materials for 8 hours per day, determine the number of trucks needed daily. 2 February 2019 COTM 4202 20
  21. 21.  Material properties have a direct effect on the ease or difficulty of handling the material, on the selection of equipment, and on equipment production rates.  Quantities are often measured in volume units.  Volume of material under different conditions varies appreciably.  Material properties have a direct effect on the ease or difficulty of handling the material, on the selection of equipment, and on equipment production rates.  Quantities are often measured in volume units.  Volume of material under different conditions varies appreciably. 2 February 2019 COTM 4202 21
  22. 22.  Bank: Material in its natural state. Also called in-place or in-situ. Measurement: BCM (Bank Cubic Meter)  Lose: material that has been excavated or loaded. Measurement: LCM (Lose Cubic Meter)  Compacted: Material after compaction: Measurement: CCM (Compacted Cubic Meter) 2 February 2019 COTM 4202 22  Bank: Material in its natural state. Also called in-place or in-situ. Measurement: BCM (Bank Cubic Meter)  Lose: material that has been excavated or loaded. Measurement: LCM (Lose Cubic Meter)  Compacted: Material after compaction: Measurement: CCM (Compacted Cubic Meter)
  23. 23. Swell Factor Shrinkage Factor  The swell factor is the ratio of the loose dry weight per unit volume to the bank dry weight per unit volume. Loose dry unit weight Swell Factor (w) = _____________________ Bank dry unit weight Swell% = ( 1/w – 1 )x100  The shrinkage factor is the ratio of the compacted dry weight per unit volume to the bank dry weight per unit volume: Compacted dry unit weight Shrinkage Factor = _________________________ Bank dry unit weight Shrinkage % = ( SrF – 1 )x100 Shrinkage Factor  The shrinkage factor is the ratio of the compacted dry weight per unit volume to the bank dry weight per unit volume: Compacted dry unit weight Shrinkage Factor = _________________________ Bank dry unit weight Shrinkage % = ( SrF – 1 )x100 2 February 2019 COTM 4202 23
  24. 24. 2 February 2019 COTM 4202 24
  25. 25.  Let w denote the swell factor of the soil  wPe denote the daily volume of loose excavated materials.  Then the approximate number of haulers required to dispose of the excavated materials is given by:  Let w denote the swell factor of the soil  wPe denote the daily volume of loose excavated materials.  Then the approximate number of haulers required to dispose of the excavated materials is given by: 2 February 2019 COTM 4202 25
  26. 26.  Equipment productivities at job sites are influenced by actual work conditions and a variety of inefficiencies and work stoppages.  Let F1, F2, ..., Fn, denote factors that lower productivity, each of which is smaller than 1,  Then the actual equipment productivity R' at the job site can be related to the standard production rate R as follows:  Equipment productivities at job sites are influenced by actual work conditions and a variety of inefficiencies and work stoppages.  Let F1, F2, ..., Fn, denote factors that lower productivity, each of which is smaller than 1,  Then the actual equipment productivity R' at the job site can be related to the standard production rate R as follows: 2 February 2019 COTM 4202 26
  27. 27.  The actual cycle time T' at the job site is related to the standard cycle time T as: 2 February 2019 COTM 4202 27
  28. 28.  A power shovel with a dipper of 1.2 cubic meter capacity has a standard production rate of 960 cubic meter for an 8-hour day. 4min is consumed to fill and load. Determine the job site productivity and the actual cycle time of this shovel under the work conditions at the site that affects its productivity as shown below:  Work Conditions at the Site Factors Bulk composition 0.954 Soil properties and water content 0.983 Equipment idle time for worker breaks 0.8 Management efficiency 0.7  A power shovel with a dipper of 1.2 cubic meter capacity has a standard production rate of 960 cubic meter for an 8-hour day. 4min is consumed to fill and load. Determine the job site productivity and the actual cycle time of this shovel under the work conditions at the site that affects its productivity as shown below:  Work Conditions at the Site Factors Bulk composition 0.954 Soil properties and water content 0.983 Equipment idle time for worker breaks 0.8 Management efficiency 0.7 2 February 2019 COTM 4202 28
  29. 29.  A dump truck with a capacity of 6 cubic meter is used to dispose of excavated materials. The distance from the dump site is 4km and the average speed of the dump truck is 30 kph. The job site productivity of the power shovel per day is 504 cubic meter, which will be modified by a swell factor of 1.1. The only factors affecting the job site productivity of the dump truck in addition to those affecting the power shovel are 0.80 for equipment idle time and 0.70 for management efficiency. Determine the job site productivity of the dump truck. If a fleet of such trucks is used to haul the excavated material, find the number of trucks needed daily.  A dump truck with a capacity of 6 cubic meter is used to dispose of excavated materials. The distance from the dump site is 4km and the average speed of the dump truck is 30 kph. The job site productivity of the power shovel per day is 504 cubic meter, which will be modified by a swell factor of 1.1. The only factors affecting the job site productivity of the dump truck in addition to those affecting the power shovel are 0.80 for equipment idle time and 0.70 for management efficiency. Determine the job site productivity of the dump truck. If a fleet of such trucks is used to haul the excavated material, find the number of trucks needed daily. 2 February 2019 COTM 4202 29
  30. 30.  A front-end loader loads a fleet of dump trucks (capacity 18 loose cubic meter each), which haul the earth to a fill where it is compacted with a shrinkage factor of 10%. The earth has a percent swell of 20%. The job requires a volume of 18,000 compacted cubic meter. Distance between quarry and project site is 5miles connected with dirt track.  How many hours will be required to excavate and haul the material to the fill.  A front-end loader loads a fleet of dump trucks (capacity 18 loose cubic meter each), which haul the earth to a fill where it is compacted with a shrinkage factor of 10%. The earth has a percent swell of 20%. The job requires a volume of 18,000 compacted cubic meter. Distance between quarry and project site is 5miles connected with dirt track.  How many hours will be required to excavate and haul the material to the fill. 2 February 2019 COTM 4202 30
  31. 31. THANK YOU! THANK YOU! 31 THANK YOU! THANK YOU! 2 February 2019 COTM 4202

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