Loading the lesson
Loading the lesson
Search AllRounder.ai
Search the courses, subjects, tracks, games and features, or jump straight to a page.
Search the courses, subjects, tracks, games and features, or jump straight to a page.
Learn it your way
A short class with Sarah and her students. The other ways are under More.
Sign up free to listen. Transcripts are free to read.
Today, we are going to discuss cycle time, which is crucial for estimating bulldozer productivity. Can anyone tell me what cycle time comprises?
Isn't it the total time taken to complete one full operation?
That's correct! Cycle time includes the push time, backtrack time, and maneuvering time. Remember the acronym 'PBM' — Push, Backtrack, Maneuver.
What factors influence the push and backtrack times?
Great question! The push and backtrack times vary based on haul distance and the machine's speed. Larger haul distances lead to longer push and backtrack times.
How do we determine the speed?
Speed can be determined using performance charts. We will discuss those next!
To summarize, cycle time is made up of push time, backtrack time, and maneuver time, abbreviated as PBM.
Let's now discuss productivity estimation. How do we calculate it?
Isn't it the blade load divided by cycle time?
Exactly! Productivity is measured in loose cubic meters per hour. Remember, it's vital to specify whether we're referring to the loose state or bank state.
What about job efficiency? How does that affect productivity?
Job efficiency reflects the actual working time of the machine. If a bulldozer operates for 50 minutes in an hour, we adjust productivity using a factor of 50/60.
So, we need to multiply the initial productivity by that efficiency factor?
Correct! Keep in mind that accurate estimations ensure proper project bidding.
In summary, productivity is calculated by blade load divided by cycle time, adjusted for job efficiency.
Now, let's talk about the cost estimation of the earthmoving operation. Who can explain what we need to calculate the cost?
We need to find the hourly cost of the machine and divide it by productivity, right?
Exactly! We must sum up all costs related to ownership and operation to find the hourly cost.
What if we underestimate these costs?
Underestimating costs can lead to inaccurate bidding and potential financial issues further down the project. That's why thorough knowledge of estimation is essential.
To sum up, to find the cost per loose cubic meter, divide hourly machine cost by productivity.
Finally, let's discuss correction factors which help adjust the productivity based on real-world conditions. Why do we need these factors?
Because the ideal conditions can differ from actual job site conditions!
Exactly! Factors include soil density, operator skill, and grading conditions. Such variations can severely impact productivity.
How do we apply those correction factors practically?
You find the ideal production from curves and apply the correction factors based on project conditions. This gives you the actual value!
In summary, correction factors adjust productivity estimates to account for real-world variations, ensuring more accurate calculations.
The total time for a bulldozer’s operational cycle, comprising push, backtrack, and maneuvering times.
The volume of material moved in a single cycle, critical for calculating productivity.
The effective working time of a bulldozer compared to its available time.
Graphical representation of expected productivity based on ideal conditions.
Adjustments made to productivity estimates to reflect real-world operating conditions.
If a bulldozer has a blade load of 2 cubic meters and a cycle time of 10 minutes, its productivity would be 12 cubic meters per hour.
To apply correction factors, if the ideal productivity from the curves is 100 cubic meters but poor visibility reduces expected productivity by 20%, actual productivity would be 80 cubic meters.
In every push and backtrack, remember the time; with PBM in mind, productivity will shine!
Imagine a hardworking bulldozer named Benny. Benny always checks his cycle time, ensures his blade load is full, and never forgets to adjust for conditions — Benny's operational success teaches everyone about productivity!
PBM for Cycle Time: Push, Backtrack, Maneuver. Each aspect is key for measurement!
PBL for Productivity: P = Push load, B = Backtrack load, L = Load volume.
Term
What are the components of cycle time?
Click to flip
Term
How is productivity calculated?
Click to flip
Term
What is job efficiency?
Click to flip
The total time taken to complete a full operational cycle of a bulldozer, comprising push time, backtrack time, and maneuvering time.
The volume of material that the bulldozer’s blade can carry, critical for calculating productivity.
The proportion of time the bulldozer operates effectively compared to the total time available, typically expressed as a percentage.
Graphs that represent the expected productivity of equipment under ideal conditions based on various factors.
Adjustments made to ideal productivity estimates to account for real-world operating conditions, such as soil density and operator skill.
This section discusses various methods to estimate the productivity of earthmoving equipment, particularly bulldozers, focusing on cycle time, blade load, and job efficiency.
The section delves into different approaches for estimating bulldozer productivity, including the calculation of cycle time based on hauling distance, the use of performance charts, and correction factors for real-world job conditions. It emphasizes the importance of accurate estimation for cost management in earthmoving projects.
In this section, the estimation of bulldozer productivity is comprehensively discussed. A bulldozer's cycle time is vital for understanding productivity, which consists of several components:
Cycle Time Components: Cycle time includes fixed times (like maneuvering time) and variable times (like push and backtrack time). Variable times are influenced by haul distance and machine speed, while maneuver time varies based on whether the bulldozer uses manual or automatic gear changes.
Estimating Cycle Time: To calculate cycle time, one needs to know the hauling distance, machine speed (determined from performance charts), and gear-changing effects.
Productivity Calculation: Productivity is expressed in loose cubic meters per hour, calculated by dividing the blade load by the total cycle time. The section details the significance of job efficiency in the calculation, which affects the effective working time of the bulldozer.
Cost Estimation: It is crucial to estimate the unit cost associated with earthmoving operations accurately, which factors into bidding for contracts. Understanding ownership and operating costs also plays a role in determining hourly costs and pricing strategies.
Correction Factors: The section explains that standard production curves from manufacturers must be adjusted with correction factors to accommodate actual project conditions, such as terrain, material type, and operator efficiency. Various factors, like soil density and traction coefficients, are discussed in relation to their impact on productivity.
Through these components, the section aims to equip the reader with the necessary tools to make accurate estimations of bulldozer productivity, thereby optimizing project planning and cost management.