Snow Removal

Graders can be used for snow removal in the same way as a snowplow. The blade and circle are adjusted to side cast snow and slush the same as if side casting road materials. When the cutting edges are not removed and replaced with a strip of hard rubber bolted to the moldboard, raise the blade at least 1/2 to 1 inch when removing snow from uneven pavement or a runway surface.

NOTE: Failure to make proper blade adjustments can result in not only damaging the cutting edges, moldboard, or grader, but also in gouging and tearing up the road or runway surface.

Finish Grading

Finish grading is a fine cut or fill of a surface to get the final desired elevation. This phase of a grading operation is called blue topping. Blue topping takes time and patience even for experienced operators.

When performing blue topping operations, make sure the grader cutting edges are not worn, the tires are the same size with the correct air pressure, and the tires are pointed in the right direction. Front tire treads should be pointed toward the rear, and rear tire treads should be pointed toward the front. Adjust the blade pitch all the way forward to scrape instead of cut.

Before making any cuts on a project, review the project grade hub stakes (blue tops) to note their location and how much you will have to cut or fill.

NOTE: Compaction of the surface must be done before finish grading can start. When you finish grading, it is better to cut 1/2 to 1 inch than to fill.

A technique used when performing blue topping operations is to divide the project into sections, working one section to final grade at a time. After the first section is to grade, you now have a reference point to start from to grade the other sections. As with any earthmoving equipment, it is best to have a level starting point.

When working each section, do not let the material build up into piles that the grader will have to run over. Windrow the material to the end or off the section and have a loader pickup the excess material and move it. If there is room, the excess material can be windrowed off the project for later removal.

When cutting, drag the blade over the top of the hub stake. Final grade is reached when the blade skims the top of the hub stake. Do not cut too deep and knock the hub stake out of the ground. When several passes are required to achieve final grade, the "cut boss" should clean off the top of the stakes so you can see them for your next pass.

Grader Estimates

A part of planning a construction project is estimating how long it will take to complete a _{construction activity.} A work-output formula for preparing preliminary estimates for grader operations is as follows:

Where

Total time = Hours required to complete a grader operation

P= Number of passes (P) the grader must take to complete the operation

D= Distance (D) traveled in each pass expressed in miles

S ⁼ Speed (S) expressed in miles per hour

E= Grader efficiency (E) factor

The most difficult factor to estimate is the speed of the grader. As work progresses on a construction activity, conditions may require that the speed estimates of the grader be increased or decreased. A work output is computed for each operation that is performed at a different rate of speed. The total time of each operation for each different speed is added together to compute the total time of the grader operation. Table 10-1 lists the speeds normally used in various grader operations.

The grader efficiency (E) factor takes into account the fact that a 60-minute work hour rarely is attained. Efficiency varies, depending upon supervision, operator skill, maintenance requirements, and site conditions. A value of 60 percent is average, computed in decimal form as 0.6. The efficiency factor can be adjusted on each job.

Example problem:

Five miles of gravel road is to be leveled and reshaped by using a grader with a 12-foot blade. Six passes are estimated to complete the leveling and reshaping operation. The type of material permits passes 1 and 2 to be performed in second gear at 2.8 mph, passes 3 and 4 in third gear at 3.4 mph, and passes 5 and 6 in fourth gear at 5.4 mph. The efficiency factor for the job is 60 percent.

Calculate how long it will take to complete the job.

Always round your answer to the next higher number. In this case, 13.88 is rounded to 14 hours.

Table 10-1.-Approximate Speed Ranges Used in Various Grader Operations