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.
Let's start our discussion today about haul routes. Can anyone tell me what a haul route is in the context of earthmoving?
Is it the path that machines take to move materials like soil or gravel?
Exactly! The haul route is crucial as it directly affects productivity and machine efficiency. Each route can vary, having slopes or flat sections, which we will quantify in terms of resistance.
What kind of resistance are you talking about?
Great question! The resistance can be both rolling resistance and grade resistance. Rolling resistance is generally constant, while grade resistance varies with the incline.
Why does the incline matter?
Good observation! The incline affects how much power is required from the machine to move its load. For example, a +5% gradient increases resistance significantly compared to flat terrain.
So, if I understand correctly, we have to calculate our resistance based on how steep it is?
Exactly! And remember this as a mnemonic: 'Rising Grades Raise Resistance' to help remember that increases in incline lead to greater resistance.
Let's summarize: haul routes are essential, and understanding both rolling and grade resistance helps us plan efficient construction operations.
Now that we know what a haul route is, how do we calculate the resistance for different sections?
Do we add up the resistance from each segment?
Spot on! We break the haul route into segments, calculate resistance for each, and sum them up. Let's take an example: for a gradient of +5%, that's 50 kg per ton. How would you express this and what would be the total for a 500-meter route?
So, for 500 meters at +5%, it stays at the same resistance, right?
Exactly! And remember this simple formula: 'Resistance (kg/ton) = Gradient (%) × 10'. So, if we have a +3% gradient for 300 meters, what’s our resistance?
It would be 30 kg per ton.
Correct! Never underestimate the math involved in construction; it’s key to success. Are we clear on resistance calculations?
Yes, we are! It’s straightforward once we know the gradients.
Let's recap: Resistance is segment-specific and requires careful calculations to forecast machine capabilities efficiently.
Next, let's discuss the swell factor. Does anyone know what it means?
Is this how we measure the difference between loose and bank volume?
Exactly! The swell factor is the ratio of loose volume to bank volume. Why is this important for scrapers specifically?
Is it because as we load more, they compact the material?
Yes! Particularly in push-loaded scrapers, the swell factor increases by 10% due to the added pressure. Can you all remember that as a mnemonic: 'Push Equals Pressure?'
What about loading capacity? How does it relate to the swell factor?
Good connection! We use the swell factor to convert the loose volume into bank volume to determine safe operating limits and prevent overloading.
Great! So if I know the volume, I can check it against our maximum capacity safely?
Absolutely! Remember: 'Volume Awareness Keeps Us Safe'. Let’s sum up: The swell factor not only measures but directly affects how we manage loads safely.
Now, let’s look at how we balance our scrapers and pushers. Why do you think this is crucial?
To make sure one doesn’t wait for the other?
Exactly! One pusher can effectively serve multiple scrapers. Do you remember the balance ratio we discussed?
I think it was the cycle time ratio between the two machines?
Very good! To balance them, we use the formula: Number of scrapers served by one pusher = Scraper cycle time / Pusher cycle time. Can someone calculate using our previous numbers?
7.78 minutes by 1.37 minutes equals around 5.68.
Correct! Now we can't have partial scrapers. So do we round up or down?
We can use both, but economically we need to evaluate scenarios.
Great insight! Let’s remember: 'Balancing is Key to Efficiency'. In summary, balancing machinery impacts time and costs. Understanding cycle time will inform better operational decisions.
The designated path for transporting materials which impacts resistance and productivity.
Can be rolling or grade resistance affecting machine performance.
A critical variable for calculating material volume changes during loading.
A vital measurement for planning operational efficiency.
For example, a hauling route with a +5% gradient would require significantly more power to traverse compared to a flat route, thus impacting the overall resistance calculations.
When calculating the swell factor, if a scraper can only carry 95% of its heaped capacity, one must determine the effective bank volume before confirming the load weight to ensure it stays within safety limits.
When hauling high, resistance will rise, keep the route flat for smoother skies.
Imagine a lumberjack pushing a heavy log up a hill. As he struggles against gravity, he realizes that every inch uphill takes twice the effort! He learns to optimize his path, finding a way to make work easier, just like scrapers finding the best haul routes with minimal resistance.
To remember the swell factor: L for Loose, B for Bank, higher by 10% when we pack!
RGR: Remember Grade Resistance adds to Rolling resistance.
Term
What is haul route?
Click to flip
Term
Define swell factor.
Click to flip
Term
What is rolling resistance?
Click to flip
Term
What is cycle time?
Click to flip
The designated path taken by earthmoving equipment during material transport.
The frictional force opposing the motion of vehicles moving on a surface.
The additional resistance encountered due to an incline or slope.
The ratio of loose volume to bank volume, reflecting changes when soil changes state.
The total time taken for a machine to complete its loading, hauling, and returning operations.
This section examines the haul route characteristics and the resistance encountered by scrapers and pushers in construction operations.
The section details the components of haul routes for scrapers, including the assessment of rolling resistance, grading, and calculations involved in estimating productivity and balancing machinery. It emphasizes the importance of understanding these factors to optimize operations and maintain machine safety.
In this section, we explore the critical aspects of haul routes and the resistance faced by earthmoving equipment, particularly scrapers and pushers. The section begins by defining haul routes and elaborating on how resistance, both rolling and grade, impacts the productivity of scrapers used for moving materials.
A significant part of the discussion revolves around segmenting haul routes based on various gradients, which are critical for calculating overall resistance. For instance:
Resistance is categorized into rolling resistance, generally constant, and grade resistance, which varies with the haul route. It is crucial to distinguish the resistance encountered in various segments to accurately estimate machine productivity and time.
The swell factor is examined to convert between loose and bank volume, considering the effect of compacting material when loaded by scrapers. The calculations involve determining an optimum loading capacity based on manufacturer specifications to avoid overloading, which can damage equipment.
The section culminates in calculating cycle times for both scrapers and pushers, emphasizing the need to balance their numbers for optimal performance. By effectively synchronizing these interdependent machines, projects can be executed more efficiently while reducing operational costs.