2. Estimating Productivity of the Bulldozer

So, this cutting and pushing will go together. So, the time required to push, backtrack and maneuver into position, so that is called as a cycle time of the bulldozer. So, you are going to cut the earth, push the earth, dump it at the required place, then backtrack, backtrack in the sense you are going to return, return back to the original position where you want to do the dosing operation again.

The cycle time of the bulldozer is a crucial measure that includes all the actions the bulldozer performs during a single complete operation. This involves three main activities: cutting the earth, pushing it to the desired location, and then returning to the starting point (backtracking) to repeat the operation. The combined duration of these activities defines the cycle time, which is a vital metric for estimating productivity.

Imagine using a shovel to dig soil, load it into a wheelbarrow, and then push the wheelbarrow to a location to dump the soil. After dumping, you return to start the process again. Just like in this scenario, the time it takes to complete all these actions with the bulldozer equates to the cycle time.

So, we call this as fixed time, this is fixed time and this one is variable time, your push and backtrack it is called this variable time, why do we call this push time and backtrack time as variable time? Because it is variable depending upon your haul distance. So, greater your haul distance greater will be a push time and return time or backtrack time. So, this is solely dependent upon your haul distance, so this is dependent upon your haul distance, so that is why we call it as variable obviously it depends upon the speed also.

Cycle time comprises fixed and variable elements. The fixed time relates to maneuvering, which is mostly constant, while the variable time corresponds to the push and backtrack stages, which fluctuate based on the haul distance. The longer the distance the bulldozer has to move material, the greater the push and backtrack times. Additionally, these times can also vary depending on the speed at which the bulldozer operates.

Think about driving a car to deliver packages. If you have to drive 5 miles, it will take you a certain amount of time to reach the destination (variable, based on distance). However, regardless of the distance, you will spend some time at traffic lights and stop signs (fixed). The total time is the sum of both the variable and fixed times.

To know the push time and the backtrack time, I need to know the travel distance or the dozing distance or the haul distance. I need to know the travel distance and I also need to know the speed. So, you very well know how to determine the speed. So, in the earlier lecture, I discussed about how to determine the speed from the performance chart.

In order to calculate push time and backtrack time, two critical factors need to be established: the travel or haul distance, and the speed of the bulldozer. The speed can be determined using a performance chart, which relates the speed to the resistance faced by the bulldozer in a given operational environment.

Using a bicycle as an analogy, to estimate how long it will take to reach a destination, you would first measure the distance to your destination and then know your cycling speed. With this information, you can easily calculate the time needed to get there.

So, now let us see what is this maneuver time? So, already I told you maneuver time is nothing, but the time needed for changing your speed accelerating, changing the gears, or reducing the speed, so that is what is called as a maneuver time. So, this maneuver time will depend upon the type of transmission.

Maneuver time refers to the period it takes for the bulldozer to adjust its speed or change gears during operations. This time is influenced by the type of transmission system used: either direct (manual shifting) or automatic (power-shift). Each type has different time requirements for changing gears, which directly affects overall cycle time.

Consider editing a document on your computer: if you have to press a lot of buttons to change formatting manually (direct transmission), it'll take longer than if you had a smart format tool that instantly handles changes for you (automatic transmission).

So, let us see how to estimate the productivity of the bulldozer. So, we are going to estimate the productivity a lose meter cube per hour. As I told you whenever you express the volume, you should be very specific that whether you are expressing the volume in the loosen state or bank state, that is natural state or in the compacted state.

To estimate a bulldozer's productivity, the output needs to be measured in loose cubic meters per hour. It is crucial to clarify whether this measurement is of loose material (as dug) or in its bank state (natural state before digging). Understanding this distinction helps in accurately conveying the bulldozer's productivity.

Consider measuring how much flour you have before and after sifting: the volume of flakes observed after sifting (loose state) differs from tightly packed flour in its original bag (bank state). Knowing which state you're measuring can change the way you comprehend the quantity.

So, it is nothing but your blade load divided by the cycle time. So, how to determine the blade load just now we discussed. So, you can get it from the manufacturer, what is the blade capacity or from your own past experience you can get it. Or you can do the field measurement yourself and find the dimension of the pile of material lying in front of the blade and determine the blade capacity.

Bulldozer productivity can be calculated by dividing blade load (the capacity of the bulldozer's blade to carry material) by the cycle time (the total time taken for one complete operation). Blade load can be determined from manufacturer specifications, previous field experience, or by measuring the pile of material directly.

Think of it as trying to fill a bucket (blade load) in a well (cycle time). The more efficiently you can fill that bucket and haul it up (shorter cycle time), the better productivity you have.

So, after estimating this, you have to take into account the job efficiency. So, one thing you should know that your machine is not going to be operated for the entire 60 minutes in an hour. So, depending upon your project condition, it may operate for 45 minutes or 50 minutes. So, it may even operate only for 30 minutes, it depends upon your project condition.

When estimating productivity, it is vital to consider job efficiency, which accounts for the actual time the machine operates within an hour. This realized time may vary based on project conditions and can be less than 60 minutes, impacting the overall productivity calculation. Hence, the effective working time must be considered while performing calculations.

If you are completing homework and spend some time getting distracted (similar to operational downtime), you won't be able to finish all the questions in one hour. Your actual 'working' time is less than that hour, just like a bulldozer may not work continuously throughout its scheduled time.

This is a very important because as I told you, when you prepare for bidding when you plan for bidding in unit rate work, in unit rate contract unit rate work. We are very much interested in this data, what is the unit cost associated with every activity, unit cost of earthmoving operation.

Understanding the unit cost of production is key, especially when preparing for bidding on contracts. This involves calculating costs related to operating the bulldozer per unit volume of material moved (e.g., per loose cubic meter). This financial context aids decision-making and helps in providing accurate bid estimates.

Imagine planning a catering service: you need to know how much each dish costs to prepare in order to estimate your total costs and price your services correctly. Just as in catering, accurately estimating production costs for earthmoving is crucial for effective business planning.

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