Question

A contractor works to explore using a 7U blade on a 240 hp dozer. The material is a dry, noncohesive silty sand and must be moved a distance of 200 ft from the beginning of the cut. It is estimated the material will swell 4%, from bank to loose state. Both visibility and traction should be satisfactory. Job efficiency is assumed to be equivalent to a 50-min hour. The U-blade width is 13 ft 1 in with 3.25 ft of wing width, and a height of 5 ft 1.1 in. The wing angle is 28.0 deg. Assume an average push speed of 3 mph and a return speed of 4 mph. Calculate the direct cost of the proposed earthmoving operation in dollars per bcy. Assume that the O&O cost for the dozer is $89.50 per hour and the operator's wage is $19.00 per hour plus 30% for fringes and worker's compensation.

Answer 1

Solution:

Solution :- Step!:- Ideal maximum Production - A DTH dozer with 70 blade and distance of zooft "Dozing production estimating curves for catepila, D7 through d dozers equiped with universal blades" Step2: Ideal production = 4301 cykle the (From table, material weight correction facts: Bank weight for this project material is given as llopf 110 blcf x 27 cflcy = 2970 lb/bcy Assume swell as 12% The loose weight of the material 2970 = 2652 lb licy 1.12

Standard Condition is 2300 A blacy = 2300 material weight correction 2652 0.87 Step 3: for operatol skill operato correction facts: From the table correction facts excellent Operats it is 1.00 Fol correction facts :- Step 4: material - type Doze blade, are designed to cut material and to roll the cut material in front of the blade Fo dey non cohenic material it is 0.80 Steps operating - Technique correction fairs: - Fol slot dozing opeeating techinque it is 1.50 steps: visibility correction furd:- for good visibility it is 1.00 stept: Efficiency ticiency fai facts: The assumed no. of operating minutes Pel hou divided by 60 min

For the job efficiency of 50-min hour is 0.83 Step 8: machine transmission facts. Correction facts for power shift transmission is 1.00 stepa: Blade Adjustment factor Blade Adjustment facts is 1.00 step 10: Grade correction factol: (-) - favouable it) un favowable Find the percent grade on the bottom of the scale move up vertically and intercer the grade correction Curve the move left holizontally and locate the grade correction facro on the vertical scale. Grade fairs 0.95 for 1-2 grade) Step 11: Determine the product of the correction facts: Product correction factors = 0.87X1X0.8 x 1.20x) x 0-83x10.95 = 0.659 step 12: Determine the Doze production : production = 430 x 0.659 = 2.83 cylha

Step 13: Determine the material converiont: - 283 = 253 cylhr 1.12 Step 14: Determine the total cost to opucto the Doze:- Cost : ofo opelato Fingers - - - $ 89.50 per how $ 19.00 $ 19.00 80.3 Total = $ 114.20 pe hou stepis: Determine the Direer unit production Cost: Il ll. 20 Direct product cost = f' 253 beylne = 0.451 pu day