Before making any cuts on a project, review theproject grade hub stakes (blue tops) to note their locationand how much you will have to cut or fill.NOTE: Compaction of the surface must be donebefore finish grading can start. When you finishgrading, it is better to cut 1/2 to 1 inch than to fill.A technique used when performing blue toppingoperations is to divide the project into sections, workingone section to final grade at a time. After the first sectionis to grade, you now have a reference point to start fromto grade the other sections. As with any earthmovingequipment, it is best to have a level starting point.When working each section, do not let the materialbuild up into piles that the grader will have to run over.Windrow the material to the end or off the section andhave a loader pickup the excess material and move it.If there is room, the excess material can be windrowedoff the project for later removal.When cutting, drag the blade over the top of the hubstake. Final grade is reached when the blade skims thetop of the hub stake. Do not cut too deep and knock thehub stake out of the ground. When several passes arerequired to achieve final grade, the “cut boss” shouldclean off the top of the stakes so you can see them foryour next pass.Grader EstimatesA part of planning a construction project isestimating how long it will take to complete aconstruction activity.A work-output formula forpreparing preliminary estimates for grader operations isas follows:W h e reTotal time =P =D =S=E =Hours required to complete a graderoperationNumber of passes (P) the gradermust take to complete the operationDistance (D) traveled in eachpass expressed in milesSpeed (S) expressed in miles per hourGrader efficiency (E) factorThe most difficult factor to estimate is the speed ofthe grader. As work progresses on a construction10-15activity, conditions may require that the speed estimatesof the grader be increased or decreased. A work outputis computed for each operation that is performed at adifferent rate of speed. The total time of each operationfor each different speed is added together to compute thetotal time of the grader operation. Table 10-1 lists thespeeds normally used in various grader operations.The grader efficiency (E) factor takes into accountthe fact that a 60-minute work hour rarely is attained.Efficiency varies, depending upon supervision, operatorskill, maintenance requirements, and site conditions. Avalue of 60 percent is average, computed in decimalform as 0.6. The efficiency factor can be adjusted oneach job.Example problem:Five miles of gravel road is to be leveled andreshaped by using a grader with a 12-foot blade. Sixpasses are estimated to complete the leveling andreshaping operation.The type of material permitspasses 1 and 2 to be performed in second gear at 2.8mph, passes 3 and 4 in third gear at 3.4 mph, and passes5 and 6 in fourth gear at 5.4 mph. The efficiency factorfor the job is 60 percent.Calculate how long it will take to complete the job.Always round your answer to the next highernumber. In this case, 13.88 is rounded to 14 hours.Table 10-1.-Approximate Speed Ranges Used in VariousGrader Operations
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