2.2. Factors Affecting Unit Cost

And hope you remember these curves are valid only for these ideal conditions. So, 60 minutes hour but in your project in this problem we found that the machine is working for 50 minutes an hour. So, you are supposed to apply the job efficiency, you have to apply the correction factor accordingly.

In any calculation of unit cost for earth moving operations, we begin with ideal conditions outlined in curve charts. These curves assume that a machine works for a full hour (60 minutes). However, in practical scenarios, you may find that the machine operates for less time due to various factors such as downtime or slower work pace. For instance, if a machine operates for only 50 minutes in an hour, we must adjust our calculations to reflect this reduced 'job efficiency' by applying a correction factor.

Think of a student preparing for an exam. The ideal study plan may suggest studying for a full two hours uninterrupted. But if the student can only focus effectively for one and a half hours due to distractions, they must adapt their study plan (just like we adjust our calculations) to account for that lost time.

But this curve value is applicable for a soil density of 1365 kg per meter cube. So, in our case the soil density is given us 1750 kg per meter cube in bank state that is to be noted the soil the bulldozer is going to do is of density 1750 kg per meter cube in bank state that is to be noted. But the curve, the production value what you have chosen from the curve corresponds to the productivity of 1365 kg loose meter cube. So, we need to compare both this material, now apply a correction factor accordingly.

Different soil types and densities can greatly affect the productivity of a bulldozer. The ideal production curves assume a soil density of 1365 kg/m³. However, if the actual soil density is 1750 kg/m³ (as in our case), we must determine a correction factor that reflects this difference. This means that the machine's expected productivity based on the ideal curve must be adjusted downward to realistically match the performance with the denser soil.

Imagine a person trying to run a race through mud versus a flat track. Running through mud (denser soil) requires more effort and will slow them down, similar to how a bulldozer's speed is affected by the density of the earth it is moving. Thus, we need to recognize this challenge and adjust our expectations accordingly.

Then other things like operator the curve was drawn for excellent operator skill. So, in our problem the operator skill is average. So, accordingly you have to choose the correction factor and apply. So, your correction factor is going to be less than 1, because it is average is going to reduce your productivity.

Operating machinery efficiently requires skill and experience. The production curve is drawn assuming the operator is highly skilled. However, if the operator is less experienced, we must apply a correction factor that decreases productivity. This adjustment, which has a value of less than 1, reflects the reduced efficiency and potential errors that may occur with an average operator.

Consider a chef preparing a complicated dish. A highly skilled chef will get it done quickly and perfectly, while a novice might take longer and make mistakes. Hence, just as a chef's skill influences the cooking time, an operator’s ability also significantly impacts the bulldozer's productivity.

Similarly, the material type, material type is non-cohesive silty sand, so that will definitely reduce the productivity. So, the correction factor is going to be less than 1.

The type of material being moved affects productivity. Non-cohesive materials like silty sand can be more difficult to manage, as they may not hold together well, leading to inefficiencies in movement. Therefore, for such materials, a correction factor is applied that is less than 1, indicating a decrease in expected productivity when compared to moving cohesive materials.

Imagine trying to build a sandcastle with dry sand that keeps falling apart (non-cohesive). It takes much longer to work with this material compared to wet sand that holds its shape (cohesive), illustrating why the bulldozer’s performance on different materials may vary.

Slot dozing, you have a lot of slot dozing method in your problem so that means that will help to increase productivity. So, your correction factor is going to be greater than 1.

Slot dozing is a technique that allows bulldozers to improve their efficiency in moving materials. When this method is employed, we can expect an increase in productivity, hence applying a correction factor greater than 1 to account for this enhancement. This technique effectively utilizes the bulldozer’s power and blade design to maximize material transfer.

Think of a delivery person who efficiently organizes their routes to drop off multiple packages rather than making multiple trips back to the same location. By optimizing their route (like slot dozing), they can complete their deliveries faster, similar to how this method simplifies the bulldozer's work.

Visibility is poor in the problem what we have discussed. So, that will reduce your correction factor, the productivity will reduce obviously we are working for 50 minutes an hour, so accordingly the correction factor should be applied.

Visibility on a job site can significantly affect a bulldozer’s productivity. Poor visibility due to factors like fog or dust can lead to slower operation and increased caution from the operator. As a result, a correction factor is required to reflect this decrease in expected productivity, ultimately reducing the overall effectiveness during the operating period.

Consider driving a car in heavy rain; the driver must slow down to be safe. Similarly, if a bulldozer operator can’t see well, they must lessen their speed and be more cautious, resulting in less material being moved in the same amount of time. This mirrors how conditions impact performance.

So, in this problem we are moving down the hill, so the grade percentage is -15%. So, accordingly you have to choose the curve supply by the manufacturer. So, corresponding to what is -15% you have to find the correction factor.

The grade of the terrain, whether flat, inclined, or declined, affects a bulldozer's efficiency. A negative grade, such as -15%, indicates the machine is moving downhill, which can enhance productivity. Therefore, for descending terrain, a correction factor greater than 1 may be applied, reflecting the ease of movement that comes with gravity’s assistance.

Imagine riding a bicycle down a hill as opposed to pedaling uphill. Coming down (negative grade) requires less energy and allows for quicker speeds, just like how a bulldozer pushing material downhill can work more efficiently than on a flat or uphill surface.

So, that is nothing but your hourly cost associated with the machine divided by the hourly productivity. If you know both these values, this you have to calculate in the bank meter cube per hour.

To calculate the unit cost of production for earthmoving operations, you take the total hourly cost of operating the machine and divide it by the machine's productivity expressed in bank meter cube per hour. This gives you the cost per unit of material moved, an essential figure for bidding and budgeting in construction projects.

Think of a candy store that sells each bag of candy for $5. If it costs the store$50 to make 10 bags, the cost per bag is $5 (total cost divided by the number of bags). Similarly, calculating the bulldozer's operational costs relative to its production gives the cost per unit of material moved.

So, the cost data is given to you directly, already you know in the previous lectures we have seen worked out, we have seen how to estimate the cost associated with the various machines.

In assessing the unit cost, first, we need to determine both the ownership costs (such as purchase or lease of the equipment) and operating costs (such as fuel, maintenance, and labor). This information provides the necessary data to derive the overall cost per hour of running the bulldozer, which is a crucial component when estimating unit costs for projects.

Consider a bakery where ownership costs include the price of ovens and mixers, while operating costs involve ingredients and employee wages. To figure out how much each cake costs to make, the bakery must analyze both costs just like we do with bulldozer operating costs.

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