2. Erection of Tower Crane with Climbing Cage

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.

Before the tower crane can be erected, a strong foundation is essential. This foundation must be heavy and reinforced with appropriate materials to support the structure's weight. After completing the initial sections of the tower structure, these sections are anchored to the foundation securely. This process ensures that the crane has a stable base to operate safely.

Think of the foundation of a tower crane like the foundation of a skyscraper. Just as a building requires a solid base to stand tall and secure, the tower crane needs the same type of strong foundation to ensure it functions properly without risking collapse.

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.

Once the foundation is ready, the next step involves erecting the foundational components of the tower crane, including the turntable, climbing cage, operator cap, and the tower top. This step requires the assistance of a mobile crane, which will provide the necessary lift to position these components accurately. The climbing cage is equipped with a hydraulic jack system that enables it to raise and lower the crane as needed.

Imagine setting up a large umbrella. You need another person to help hold it while you fix the pole in place and adjust the umbrella's height with its hydraulic mechanism. Similarly, a mobile crane helps position the key parts of the tower crane before it becomes operational.

So, the first, you put the foundation few sections of the tower mast you erected, bolted to the foundation then erect your climbing cage, your turntable or the slewing ring and the operator cap. 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.

After setting up the initial components, the next step involves attaching the counter jib, which stabilizes the crane and keeps it balanced by using counterweights. It’s crucial to start with a few counterweights and gradually increase the jib portion to ensure stability. This careful approach helps maintain balance while the crane is in operation.

Think of a seesaw in a playground. If one side has too many kids and the other has none, it’ll tip over. To balance it, you would add kids gradually to the lighter side. Similarly, the counter jib and weights of the tower crane ensure that it maintains balance while performing lifts.

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.

With the initial assembly complete, the process of self-erection can now begin. This involves adding additional sections to the tower crane to increase its height. A method known as 'trolling' is used, where a new section is brought closer to the existing structure in preparation for attachment.

Imagine a stack of toy blocks. Once you've built a few layers tall, you want to make it even taller. You would slide another block into place just underneath the last layer, which is like the trolling action that brings the new section in line for attachment to the crane.

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. So, that you can create the space to introduce a new section.

After successfully trolling the new section into position, the turntable base needs to be unbolted and lifted to create space for the new section to be attached. The hydraulic jack within the climbing cage performs this lift, allowing the crew to connect the new section to the structure securely.

Think about adjusting the height of a lamp by lifting its shade. You first have to loosen it or unbolt it before you can slide it higher or lower. In the crane’s case, when the turntable is lifted, it allows for a new section to fit securely just like adjusting that lamp's height.

You are going to create a space below the turntable. So that you can introduce a new section below the turntable. Now, once the space is created, now, you introduce a section into this space into this climbing cage. Now, you bolt the new section to the turntable as well as to the remaining portion of the tower. So, that is how the new section is now connected. So, like this, you can keep on adding the sections.

Once the space is made by lifting the turntable, the new section is positioned and bolted securely to both the turntable and the existing tower structure. This allows for multiple sections to be added during the self-erection process until the desired height is achieved.

Building a LEGO tower, after modifying a base element, you simply add another block on top. The connection is made strong, allowing you to keep stacking higher just like adding sections to the tower crane.

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.

The dismantling process of the tower crane with a climbing cage occurs in reverse order of the erection process. The sections are removed one by one, often facilitated by a mobile crane if necessary, and components like the jib and counter jib are also taken off, ensuring safe and efficient disassembly.

Taking apart a piece of furniture can be similar; you unscrew and remove one part at a time, like legs or shelves, until it’s all dismantled safely. You might need a friend’s help for larger pieces, much like how a mobile crane assists in removing larger components of the crane.

Another important thing, you need to know that is the maximum free standing tower crane height permissible is 60 to 120 meter. So, beyond 120 meters, the tower crane should take the help from the structure. You should properly brace it to the nearby structure to transfer the overturning movement to the structure from the stability point of view.

Tower cranes have height limitations that must be followed to ensure safety and stability. The maximum free-standing height generally ranges from 60 to 120 meters. If the crane needs to operate at heights beyond this limit, it must be braced and secured to the building structure itself to manage the forces acting on it.

When scaling a tall ladder, you would want to secure the ladder to something stable, like a wall, particularly if you reach a great height. Just as you need that extra support to avoid falling, taller cranes must also be secured to prevent losing stability.

If there is no climbing cage, we need the support of another mobile crane for the entire process. Say, first, you have to remove the trolley part you have to remove the trolley. So, after removing the trolley, you remove the counterweights. You remove the counterweights then you remove the jib. So, then you remove the counter jibs.

In cases where a climbing cage is absent, the entire dismantling process becomes more complex and requires a mobile crane throughout. The procedures include systematic removal starting from the trolley, followed by counterweights, the jib, and finally, the counter jibs, ensuring everything is taken down safely and correctly.

Imagine taking down a large tree house without a ladder. You might need a team of friends to help you reach different parts and carefully dismantle sections. You remove one piece at a time, employing the support of friends, just like you would use a mobile crane to help take apart a tower crane without added support.

Say, for example, you need a tower crane for a structure which is greater than 300 meters. In that case, what is the option available? There are certain special cranes called as climbing tower cranes which can grow along with the structure.

For buildings exceeding 300 meters, traditional tower cranes are insufficient. Climbing tower cranes are specifically designed to adapt to the building's height, allowing them to be supported by the structure as it rises. This ensures that they can safely function at greater heights by shifting their support point as new floors are added.

Think of a plant growing beside a trellis. As it grows taller, it might latch onto the trellis for support, helping it reach even greater heights than it could on its own. Similarly, climbing tower cranes 'attach' to a building to grow higher and continue operating safely.

--