2.3. Self-Erection Procedure

Now, let us see how the erection of the tower crane is done with climbing cage. In modern tower cranes, we have this climbing cage facility which facilitates the self erection process of the crane. So, basically, what you have to do is first, you have to prepare the foundation for the tower crane that is very important. You have to prepare a heavy foundation for the tower crane according to the requirement, put heavy reinforcement and then both the tower sections to the foundation after construction of the first few sections of the tower crane.

The first step in the self-erection procedure for tower cranes is to prepare a suitable foundation. This foundation must be heavy and fortified (reinforced) to support the weight of the crane and the loads it will lift. After constructing this strong base, the initial sections of the tower crane are securely attached to this foundation, ensuring stability while the crane is erected.

Imagine building a tall bookshelf; before placing it up, you first need to make sure it has a strong base. Just like you wouldn't put a heavy bookshelf on a flimsy table, a tower crane needs a robust foundation to keep it from tipping over.

Now, what you do is, you erect your turntable or this slewing ring, operator cap and the tower top. For all these things, we need the support of another mobile crane. With the help of another mobile crane, you erect the turntable, climbing cage, this is your climbing cage, climbing cage with the hydraulic jack system. You will be seeing a hydraulic cylinder here which helps the lifting.

After the foundation is prepared, the next step involves lifting various components of the tower crane such as the turntable, operator cap, and tower top. This requires a second mobile crane to provide the necessary lifting power. The climbing cage, which is a key component of the self-erection process, includes a hydraulic jack system that allows for better maneuverability and control when lifting these heavy parts into place.

Think of lifting a heavy lid onto a storage box. Instead of trying to lift it directly with one hand, you might ask a friend to help lift it at the same time, which makes the job much easier. Here, the second crane acts like that friend, helping to position the heavy parts into place.

And the tower top, you erect it. Then now, you put the counter jib with few counterweights. First, you put few counterweights, then slowly increase the jib portion. As you increase the jib portion sections, you can increase the number of blocks here; number of counterweight blocks. Now, when this is done, till this, you need the support of another mobile crane.

Once the initial setup is complete, the next step is to add counterweights and the jib (the horizontal arm of the crane). Counterweights are added first to balance the structure, preventing it from tipping over. As the jib portion is lengthened, additional counterweights are incrementally added to maintain stability. During this phase, assistance from the mobile crane is still required to manage the heavy lifting and positioning of the components.

This is like building a seesaw. When one side is heavy, you have to add weights to the other side to keep it balanced. If one half of the seesaw gets too long without extra weight, it could tip over. Similarly, the crane's long jib needs heavier counterweights to stay balanced.

Once this is done, then you can do the self-erection of the tower crane. So, how to do that? First, what you do is, you have to introduce a new section to increase the height of the tower crane with the help of trolling action. You know the trolling rate. There is a trolley here in the main jib. By the trolling action so, you can bring the, you see, here you can see, this is a new section. The new section is brought closer to the tower with the help of the trolling action.

After establishing the base and adding elements, the next operation is the self-erection process itself. To increase the height of the tower crane, a new section is introduced using a 'trolley action.' The trolley, located in the main jib, allows the new section to be moved closer to the existing structure efficiently. This process marks the transition from needing external assistance to being able to self-manage the crane's height.

Think of the way you can extend a telescope. You don’t need someone to help you every time—once you know how to pull the sections apart, you can adjust it as you want. Similarly, the crane can now 'grow' taller on its own by adding sections.

Now, what you do is unbolt your turntable base, unbolt your turntable base, unbolt it and lift it with the hydraulic jack in the climbing cage. This blue colour one is your climbing cage. So, this has a hydraulic cylinder, hydraulic jack system, you can see here. So, now, you unbolt the turntable and lift it with a hydraulic jack.

Once the new section is brought into position, it's time to secure it in place. This involves unbolting the turntable base and using the hydraulic jack system within the climbing cage to lift it slightly. By lifting the base, a space is created, allowing for the new section to be bolted onto both the turntable and the main structure of the tower. This ensures the new height is stable and securely integrated into the crane's existing framework.

Imagine you’re adding another floor to a Lego tower. You first have to remove a piece to make space, then carefully place the new block on top before securing it in place. This is how the turntable releases its load and accommodates new sections.

Every time, you have to do the trolling action and bring the new section near the tower and lift the turntable, unbolt the turntable, lift the turntable with the hydraulic jack, then introduce a new section, then again bolt it. Like this, you can keep on adding the sections.

The self-erection process follows a systematic pattern. To repeat the process of adding height, you will always use the trolley action to bring each new section close to the tower. After lifting and securing the turntable again, the new section is firmly fastened into the tower structure. This method allows for progressive height increase in a controlled and efficient manner, shaping the final form of the crane.

This is like stacking boxes on a shelf; you keep taking the next box, positioning it carefully, and putting it in place one at a time until your shelf reaches the height you want.

Similarly, if you want to dismantle it, you do the entire thing in the reverse order. So, you can remove the section one by one with the tower crane. After the desired height is reached with the help of another mobile crane, you can remove the jib and the counter jib portion.

When it comes time to take down the crane, the process is essentially the reverse of building it up. You’ll need to remove sections one at a time, starting with components like the jib and counter jib. Once you’ve finished the construction and reached the final height, the assistance of another mobile crane is required again to manage the removal of the larger pieces. This ensures the crane is safely dismantled without any risk of collapse.

Think of it as taking apart a tent. You start by removing the poles and the outer fabric first, followed by smaller components, until everything is neatly packed away. Just like the crane, a careful reverse order ensures stability throughout the dismantling process.

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