4.5. Tandem Power Machines

So, similarly, another example on hauling of earth as I told you the hauling of earth or you can either go for a truck, even the scraper what we saw in the earlier slide the scraper also can is good for a hauling distance up to 1000 meter it is economical. So, even you can go for a scraper for hauling of earth. So, there are different hauling machines available you can either go for a truck, which is the best hauling equipment or you can go for a front end loader. So, for shorter distances, say up to 100 meters you can go for front end loader or you can go for a conveyor belt. So, productivity requirement is more so, everything depends upon your job requirement. So, you work out the options workout the economics of all these options and whichever gives you the lesser unit production cost go for that particular option.

When deciding on the best machine for hauling earth, there are several options available, including trucks, scrapers, front end loaders, and conveyor belts. For longer distances up to 1000 meters, scrapers can be economically viable. For shorter distances, like 100 meters or less, front end loaders and conveyor belts are more suitable because they offer efficient transport. Ultimately, the choice of equipment hinges on the specifics of the job requirement, particularly the distance to be covered and economic considerations, like the unit production cost.

Think of it like deciding on the best vehicle for a road trip. If you're going cross-country (like hauling earth for a long distance), you might choose an RV (scraper) for comfort and space. But if it’s a quick trip to the grocery store (short distance), a car (front end loader) is quicker and more fuel-efficient.

Similarly, another example if you see about the concrete placement, so, you are prepared your concrete in your concrete mixer machine, now you need to transport the concrete to your formwork where it has to be placed. So, there are different ways different methods of placing the concrete either I can go for this chute in claim pipeline, to place a concrete, if the distance is going to be shorter it can go for a chute or you can go for a power driven buggy like this which can easily carry the concrete from the mixer machine. And take it to the formwork or you can even go for a pumping method which is more popular. Concrete pumping is commonly adopted for placement or you can go for a conveyor belt like this. If the placement requirement rate, the rate of placement needed is very high or they can go for even crane with buckets, if the concrete to be placed at a greater height, then I have to go for crane with concrete buckets even we can even go for a helicopter with concrete bucket depending upon your job site condition.

After preparing concrete in a mixer, it must be transported to the formwork. There are numerous methods to achieve this. For shorter distances, a chute or a power-driven buggy may be used for quick transportation. For larger projects where a high placement rate is needed, concrete pumping is the preferred method due to its efficiency. Other methods include using conveyor belts for ongoing needs or cranes with buckets for high-placement situations. In extreme cases, helicopters may be utilized in hard-to-reach sites.

Imagine sculpting a figure from clay. Once it's prepared, you must transport it to the display pedestal. Using a small cart (power buggy) is fine for short distances, but for larger displays, you may need a conveyor belt or a crane to lift it to the gallery.

So, the next important factor which is going to govern the selection of the machine is your contract specification guidelines. So, what are all the guidelines which are specification in the contract documents, that is a very important guideline. But the thing is, as I told you, your contract document is only going to define the exact project time schedule and the time needed for every activity is going to be dependent on the specifications given in your contract documents. And also the budget also is clearly mentioned only in the contract documents.

When selecting construction machinery, the guidelines set forth in the contract specifications play a crucial role. These documents outline project timelines, specific tasks, and budget constraints. Sometimes, they might specify only the desired outcome (like a concrete column's strength) without detailing how to achieve it. In such cases, the contractor has the freedom to choose equipment, while clear specifications will guide methodologies and equipment selection to ensure quality results.

Think of it like following a recipe. A recipe gives you the ingredients (contract specifications) and cooking times but sometimes lacks exact instructions (like which tools you should use). A good chef will adapt based on their knowledge but will still aim to create the dish as intended.

So, another important thing apart from all is economics. So, which we need to consider is the conditions at the job site. So, the real site condition that is very important factor for selecting your machine, say the underfoot conditions that is going to decide the type of mounting needed for a machine say the terrain is going to be very rocky or it is going to be very sandy. In that case, it is not possible for us to go for this kind of wheel type machine or rubber type mounted machine. We have to go for crawler type or track type, which will have a broad contact area, better traction better stability.

The conditions of the job site significantly influence the type of machinery used. For instance, if the ground is rocky or sandy, wheels might not provide enough support or traction, making crawler or track-mounted machines a better choice. These types of machines have a larger contact area, providing improved stability and traction.

Consider a bicycle on a smooth road versus a sandy beach. On the smooth road, it’s easy to ride quickly, but on the beach, you’d struggle to pedal. Just like that, machines need to be suited for the surface they’re working on.

So, another important thing to be noted is rolling resistance that will govern the selection of machine, what is this rolling resistance? So, when your machine is moving over a particular road surface, how much resistance the particular road surface is going to offer to the movement of the machine. So that is called as the rolling resistance. So if your underfoot conditions are very poor, if it is going to be a rocky terrain or if it is going to be a very muddy terrain, so the amount of resistance offered by the haul route to the movement of vehicle will be very high.

Rolling resistance refers to the frictional force that the surface offers against the movement of a machine. In challenging conditions, such as rocky or muddy terrain, rolling resistance increases. Thus, stronger and more powerful machines (higher horsepower) are needed to overcome this resistance before they can perform their intended tasks effectively.

Think of pushing a heavy box on carpet versus on tile. On the carpet (muddy terrain), it’s harder because of the increased resistance, whereas on tile (better surface), it glides easier. Similarly, machines need more power to operate efficiently on tougher surfaces.

Another important guideline which we should keep in mind is we should always maintain the haul roads, there are so, many equipment’s to maintain the haul road, like either you can go for a grader or you can go for a compactor. So, you should maintain the haul roads clear all the short rocks so, that you can increase the travel speed of your machine. So, if you can increase the travel speed of your machine, the cycle time of the machine will be reduced. So, your productivity will increase so, your total project cost gets reduced.

Maintaining haul roads is critical for optimizing the performance of machinery used on a job site. This involves using graders or compactors to keep the path clear and in good condition. Well-maintained haul roads lead to faster travel speeds for machinery, reducing cycle times and increasing overall productivity, which in turn lowers project costs.

Imagine driving on a highway versus a bumpy back road. On a smooth highway, you can drive faster and spend less time in transit. Similarly, a well-maintained worksite allows machinery to operate more efficiently, cutting down costs and time.

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