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Interactive Audio Lesson
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Introduction to Factors Affecting Unit Cost
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Welcome class! Today we'll be discussing the factors that affect the unit cost of earthmoving operations. Understanding these factors is vital for accurate budgeting and cost predictions. Can anyone tell me why understanding cost is important in a project?
It helps us determine how much we can charge for services and what's feasible for our budget.
And it helps in making decisions about hiring and resource allocation.
Exactly! Now, one major factor is job efficiency. If a machine is designed to work for 60 minutes but only works for 50, how do you think that affects productivity?
We would need to adjust our productivity calculations downwards.
Great insight! This adjustment is often done using correction factors. Does anyone know what a correction factor is?
It's a way to account for real-world conditions affecting productivity compared to ideal conditions.
Exactly! Remember the acronym JOMV (Job Efficiency, Operator Skill, Material Type, Visibility) to help recall some of the main factors we will consider today.
Operator Skill and Material Types
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Let's talk about operator skill. If we have an operator with average skills, what impact do we think that will have on unit costs?
It will reduce overall productivity since they might not perform as efficiently as an expert.
Yeah, if they take longer to complete tasks, the costs will go up.
Exactly! And when it comes to material type, what can you tell me about using non-cohesive silty sand versus cohesive materials?
Non-cohesive materials are usually trickier to manage and may lead to lower productivity.
Right! To help remember this, think of the phrase 'Cohesive is Cooperative'. More cooperative materials help maintain performance levels.
That makes sense! So if we're working with silty sand, we should expect lower performance and adjust our cost calculations.
Visibility and Grade Impact
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Now, let’s discuss visibility. How do poor visibility conditions affect a machine's operation?
It makes it harder to navigate and operate effectively, which can slow down work.
Exactly! Poor visibility will decrease productivity so we need to include that in our correction factors. What about grade, particularly a negative slope?
A decline can actually help with productivity since gravity assists in moving the load.
That means we might even have a higher correction factor for downhill work!
Precisely! Keep this in mind next time you’re calculating costs. Let's summarize today’s key points: job efficiency, operator skill, material type, visibility, and grade all impact unit cost through their influence on productivity.
Calculating Unit Cost
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Now that we understand the factors, let's look at how to calculate unit cost. What do we need to know?
We need to know the hourly cost and the adjusted productivity.
Then, we can find the unit cost by dividing the hourly cost by the productivity.
Correct! For example, if our hourly cost is 1450 and productivity is 55.63 bank meters per hour, how much is our unit cost?
That's around 26.06 per bank meter cube!
Great job! Remember this calculation; it's heavily used in project bidding. Each factor we've discussed affects this bottom line.
So those correction factors are super important for estimating accurate costs!
Introduction & Overview
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Quick Overview
Standard
In this section, we explore several critical factors affecting unit costs in earthmoving operations. It covers the importance of job efficiency, operator skill, material density, visibility, grade, and machine transmission factors. Through correction factors, we can adjust productivity and cost estimates to match real project conditions.
Detailed
Detailed Summary
In this section, we examine the specific factors that influence the unit cost associated with earthmoving operations. Firstly, it is important to understand that productivity curves are valid only under ideal conditions. Factors such as job efficiency, operator skill, and the type of material being handled all play a significant role in adjusting these curves to reflect actual conditions.
Key points discussed include the need to apply correction factors, particularly regarding:
1. Job Efficiency: Discussion of the scenario where the machine works for only 50 minutes per hour, necessitating adjustments to productivity calculations.
2. Operator Skill: How average operator skills will reduce productivity compared to what is illustrated in the manufacturer’s curve.
3. Material Type: The impact of using non-cohesive silty sand on production, which is lower than that indicated for cohesive materials.
4. Visibility Conditions: The effect of poor visibility on productivity.
5. Grade or Slope: How a negative slope can potentially enhance productivity correction factors.
6. Material Weight: The importance of accounting for the density of soil being moved versus standard values.
Together, these factors are factored into correcting productivity estimates, which are then used to calculate the unit cost of operation, resulting in critical insights for planning and budgeting in construction and earthmoving projects.
Audio Book
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Understanding the Ideal Conditions
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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.
Detailed Explanation
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.
Examples & Analogies
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.
Soil Density Correction
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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.
Detailed Explanation
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.
Examples & Analogies
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.
Operator Skill Correction Factor
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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.
Detailed Explanation
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.
Examples & Analogies
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.
Corrective Factors for Material Type
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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.
Detailed Explanation
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.
Examples & Analogies
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 and Its Impact
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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.
Detailed Explanation
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.
Examples & Analogies
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 and Its Effects
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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.
Detailed Explanation
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.
Examples & Analogies
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.
Adjusting for Terrain Grade
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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.
Detailed Explanation
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.
Examples & Analogies
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.
Calculating Unit Cost of Production
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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.
Detailed Explanation
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.
Examples & Analogies
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.
Factoring in Ownership and Operating Costs
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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.
Detailed Explanation
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.
Examples & Analogies
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.
Definitions & Key Concepts
Learn essential terms and foundational ideas that form the basis of the topic.
Key Concepts
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Unit Cost: The cost of performing a unit of work in earthmoving operations.
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Correction Factor: Adjustments made to productivity estimates based on real-world conditions.
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Operator Skill: The proficiency level of the operator affecting productivity.
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Material Type: The classification of soil or material impacting how easily it can be moved.
Examples & Real-Life Applications
See how the concepts apply in real-world scenarios to understand their practical implications.
Examples
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If an excavator is expected to operate for 60 minutes but only operates for 50, its productivity must be adjusted downward by a factor corresponding to 50/60.
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In working with dense silty sand, productivity may be less than for cohesive materials, necessitating a correction factor of less than 1.
Memory Aids
Use mnemonics, acronyms, or visual cues to help remember key information more easily.
🎵 Rhymes Time
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To keep costs low and work go fast, check job efficiency’s in the past!
📖 Fascinating Stories
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Imagine a racecar driver who needs expert skills to win. Without practice, the race would slow down, just as a machine needs skilled operators to keep on pace.
🧠 Other Memory Gems
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Remember JOMV to recall job efficiency, operator skill, material type, and visibility.
🎯 Super Acronyms
USE the factors
- U: for Unit cost
- S: for Skill
- E: for Efficiency.
Flash Cards
Review key concepts with flashcards.
Glossary of Terms
Review the Definitions for terms.
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Term: Job Efficiency
Definition:
The ratio of actual machine operating time to the total available time, usually expressed in minutes per hour.
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Term: Correction Factor
Definition:
A numerical factor applied to adjust calculated productivity or costs based on specific project conditions.
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Term: Visibility
Definition:
The condition of how clearly workers can see during operation, often affected by weather and lighting.
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Term: Grade
Definition:
The slope of the terrain where earthmoving operations are conducted, impacting the ease or difficulty of the work.
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Term: Material Weight Correction Factor
Definition:
The factor used to adjust productivity estimates based on the density of the soil being moved.