Question

A 240 hp (power-shift) dozer is used in a pushing operation. The dozer is equipped with a straight blade. The material (dry and noncohesive) weighs 98 pcf in the bank state. It is estimated the material will swell 6%, from bank to loose state. The center-of mass-to-center-of-mass pushing distance is 200 ft. Job efficiency can be assumed to be equivalent to a 45-min hour. Calculate the production in bey per hour and the direct cost of the proposed earthmoving operation in dollars per bey. The company's normal O&O cost for these machines is $95 per hour and the operator's wage is $15.00 per hour plus 40% for fringes, insurance, and worker's compensation.

Answer 1

Answer:-

given that

A 240 hp (power-shift) dozer is used in a pushing operation. The dozer is equipped with a straight blade.

Calculate the production of the 240 hp dozer:

production (lcy per 60-min hr),

Here, Net hp is the net horse power at the flywheel for a power-shift dozer,and D is the one-way push distance in feet.

substitute 240 for net hp, and 200 ft for one-way push distance.

Calculate the material weight correction factor:

convert the bank weight of the material from lb/cu ft to lb/cu yd as below:

Bank weight (lb/cu yd)= Bank Weight (lb/feet)*27 cu ft/cu yd

Substitute 98 lb/cu ft for bank Weight (lb/feet).

Bank Weight (lb / cu yd) = 98 lb / cu.feet * 27 cu feet / cu yd

= 2646 lb/bcy

Calculate the soil density correction factor:

Soil density correction

Substitute 2646 lb/bcy for bank Weight, and 6% for swell percentage.

Soil density correction

  

Calculate the Material Weight correction factor:

Material Weight correction factor

Substitute 2300 lb/bcy for standard condition, and 2496.22 lb/cy for soil density correction.

Material Weight correction factor

  

Calculate the efficiency correction factor:

Efficiency correction factor

Substitute 45 min-hr for efficiency.

Efficiency correction factor

  

Calculate the dozer production as follows:

Dozer production

Substitute 316.8 lcy/hr for Q, 0.92 for material weight factor, 0.75 for efficiency correction factor and 60% for swell percentage.

Therefore, the dozer production is 207 bcy/hr.

Calculate the total cost as follows:

   O&O = $95

operator= $ 15+0.4(15)

= $ 21

Total cost= O&O cost+operator cost

Substitute $ 95 for O&O, and $21 for operator cost.

Total cost= 95+21

= $ 116

Calculate the cost per bcy as follows:

Substitute $ 116 for total cost, and 207 bcy/hr for production.

Therefore, the cost per bcy is .