The construction crane building process is a complex and fascinating journey that requires meticulous planning and execution. The process begins with the design phase, where engineers and architects create detailed blueprints and specifications for the crane.
The design phase involves selecting the right materials and components, such as the crane's boom, counterweight, and hoist. These components are carefully chosen to ensure the crane can withstand various environmental conditions and loads.
A critical aspect of crane design is the boom, which is typically made from high-strength steel alloys that can support heavy loads. The boom's length and configuration are carefully calculated to ensure efficient lifting and maneuverability.
The next step is manufacturing, where the selected components are fabricated and assembled into the crane's framework. This process requires precision and attention to detail to ensure the crane meets the required safety standards.
For more insights, see: Purchase Order Process
Construction Crane Components
Construction cranes are massive machines that play a crucial role in construction projects, and understanding their components is essential to their functionality and safety. The base of a tower crane is firmly anchored to the ground, ensuring the stability of the entire structure.
The mast, also known as the tower, is the vertical component that provides the crane with its significant height. This is where the slewing unit, a crucial part that allows the crane to rotate 360 degrees, is attached.
The slewing unit is connected to the jib, the long horizontal working arm used for lifting materials, and the counter-jib, which holds weights to balance the crane's load.
Key Components
A tower crane is a complex machine, but its key components are actually quite straightforward. The base of the crane is firmly anchored to the ground, ensuring the stability of the entire structure.
The mast, also known as the tower, is the vertical part that provides the crane with its significant height. This is where the crane's height comes from.
The slewing unit is a crucial part of the crane, allowing it to rotate a full 360 degrees. This is essential for getting the job done efficiently.
Worth a look: Tower Cranes
The jib is the long horizontal working arm used for lifting materials. It's the part of the crane that actually does the lifting.
The counter-jib holds weights to balance the crane's load, keeping everything stable and secure. This is a vital component that prevents accidents.
The operator's cabin is situated on top of the mast, offering a panoramic view of the construction site. This allows the operator to have precise control of the crane's operations.
Check this out: Heavy Equipment Operator Crane
Building a Crane
Building a crane is a complex process that requires precision and care. A strong foundation is built out of concrete and steel to ensure the ground can support the crane's heavy loads.
The foundation is typically built before the tower crane can be put up. The bottom section of the tower is lifted by another crane and fixed on it. Each section of the tower has a ladder inside it, allowing workers to climb up and bolt the sections together.
Recommended read: Mobile Tower Cranes
The sections of the tower are stacked on top of each other, with each one being lifted and fixed in place. A big metal ring that can spin around is attached on top of the last section of the main tower. This ring allows the driver to have a good view of their surroundings.
The driver sits in a cabin fixed to the side of the rotating ring, which is essential for safe operation. A steel frame is then lifted and fixed directly on top of the rotating ring, becoming the highest part of the tower crane.
The lifting arm, which sticks out horizontally, is then attached to the rotating ring and tied to the highest steel frame with big, strong wire ropes. The lifting arm comes in sections that are connected together by strong bolts.
Fitters wear harnesses tied to a stable point to ensure they don't fall from the heights they're working at when assembling the lifting arm. Engineers check the crane to make sure it's fixed and working perfectly before it can be used.
Engineers also keep an eye on the weather, as strong winds can make the crane unstable and potentially cause it to fall over.
Consider reading: Big Machines for Construction
Crane Structure and Types
Tower cranes are marvels of engineering that combine strength with precision. Their intricate design is a testament to modern engineering, tailored to meet the demands of various construction projects.
Tower cranes are categorized based on their structural design and functionality, with two primary types: the hammerhead crane and the luffing jib crane. Hammerhead cranes feature a fixed jib and are renowned for their higher lifting capacities and stability, making them ideal for large-scale, heavy-duty construction tasks.
Luffing jib cranes, on the other hand, are designed with a jib that can move up and down, allowing for adjustments in the working radius. This makes them perfect for projects in densely populated urban areas where space is limited.
For your interest: Jib Crane Design
Base Support
The base support is the foundation of a tower crane, typically attached to a concrete pad on the ground. This provides a solid, stable base for the crane to operate from.
The base support carries the entire weight of the crane, which is why it's essential to ensure it's securely attached to a concrete pad or a steel structure. This foundation element ensures the crane remains stable during operation.
In some cases, the base support may be connected to a steel grillage or a ballasted chassis, which can be placed on top of an existing structure or directly on the ground. This provides additional stability and support for the crane.
A tower crane's base support is usually bolted to a solid base, which can be a concrete pad or a steel structure, providing the necessary stability and anchoring for the crane. This strong base is essential for the crane's operation and safety.
Space Availability
Tower cranes are surprisingly compact, but their assembly and dismantling require a significant amount of space and support equipment.
Maxim Crane's team can assess the optimal location for your crane and plan for the necessary space to assemble and dismantle it.
The assembly process can be minimally disruptive to your construction site with careful planning.
Their team will ensure that your crane setup is efficient and meets your needs.
Hammerhead
Hammerhead cranes are the most common tower crane design, featuring a long horizontal jib attached to a vertical tower.
A trolley runs along the jib to position the hook, making it an efficient way to lift and move heavy loads.
Explore further: How Do Tower Cranes Work
Luffing Jib
The luffing jib is a type of tower crane that features a diagonal arm extending out from the top of the tower on an angle.
This design allows the hook block to be placed off the end of the jib, which can rotate up and down. This type of crane is especially useful on tight construction sites.
Unlike traditional tower cranes, luffing jibs do not use a trolley, instead raising or lowering the jib as needed for load lifts closer to the mast.
Luffing cranes are typically more expensive than other types of tower cranes.
The jib can be raised or lowered to allow the crane to swing freely in a reduced radius, making it a great option for projects in densely populated urban areas.
This flexibility in movement makes luffing jibs perfect for jobsites where space is limited.
The luffing jib crane is often referred to as a luffer, and is a popular choice for construction projects due to its versatility and efficiency.
The Evolution
The first tower cranes were derrick tower cranes, named after a type of gallows developed by Thomas Derrick, which featured a boom attached to a rotating base with a hinge.
Construction crews had to come up with ingenious lifting mechanisms because there was no way to rent tower crane equipment.
The early 20th century brought a new design, the Gantry tower crane, with a tower featuring suspended beams and trolleys, but it was less efficient due to its weight.
Hans Liebherr's design in 1949 featured a rotating tower and horizontal working arm with a 360-degree range, making construction work much easier.
This design became a major inspiration for future prototypes and paved the way for the modern tower cranes we see today.
Most manufacturers stopped making hydraulically powered tower cranes in the 1970s, switching to electric alternatives instead.
Modern tower cranes are more powerful, versatile, and energy-efficient than ever, with dozens of features that earlier crane operators could only dream of.
If this caught your attention, see: Jib Crane Design Drawings
Crane Capacity and Requirements
When choosing a crane, consider the type of materials you'll be lifting. This will help you determine the right capacity for your crane.
Lighter cranes are suitable for lifting materials like formwork and buckets of concrete. They're a good choice for smaller construction projects.
Heavier cranes are necessary for lifting equipment like generators and large steel members. These cranes can handle more weight and are often used on larger construction sites.
Critical lifts, which are typically those within 10% of the crane's total capacity, require special consideration. It's essential to choose a crane that can handle these heavy lifts safely.
The crane's typical lifts should also be taken into account when selecting a crane. This will help you choose a model that can handle the most common lifting tasks.
Here's an interesting read: Bill of Materials
Frequently Asked Questions
How do construction workers get cranes on top of buildings?
Construction workers typically use the external climbing method or internal climbing method to assemble cranes on top of buildings, or heavy-lift helicopters to transport crane parts to the site. This allows cranes to be efficiently and safely positioned for construction work.
Sources
- https://www.cmbuilder.io/post/guide-to-construction-tower-cranes
- https://simscrane.com/tower-cranes-how-are-they-built/
- https://www.maximcrane.com/blog/everything-you-need-to-know-about-tower-cranes/
- https://apcranetraining.com/blogs/how-tower-cranes-are-built-and-moved.php
- https://theconversation.com/curious-kids-how-does-a-tower-crane-go-up-and-down-210750
Featured Images: pexels.com