Different types of tower cranes

Different types of tower cranes

A tower crane is a large machine used to lift heavy building materials. It is one of the most common machines seen on construction sites. Like the name suggests, the tower crane resembles a tower. It's a large vertical pole with horizontal arms that lifts and moves objects around a building site.

The two main components of a tower crane are the vertical component (the tower) and the horizontal component (the jib).

• The tower usually sits on a concrete square that's called the "masthouse," which helps stabilize the crane. In some situations, cranes are anchored into the building itself.
• The jib extends out like an arm and can be fixed or luffed (pulled in/out at an angle). It features a trolley that moves materials horizontally. The trolley is operated by ropes and wires controlled by the crane operator from a cabin. At the end of the jib is a counterweight that balances the load being lifted.

Generally, the crane works by rotating around its own vertical mast (the tower) to pick or drop materials within a set radius. The radius depends on the type of the tower crane.

When it comes to the lifting of weights, tower cranes are further categorized into top-slewing, bottom-slewing, and flat-top cranes.

• Top-slewing tower cranes: They have their slewing mechanisms on top of their tower. Top-slewing tower cranes are appropriate for large construction projects like high-rise buildings, bridges, and infrastructure development. They can lift very heavy weights to great heights. The weight capacity of top-slewing cranes ranges from 6,000 to 20,000 kg (13,228 to 44,092 lb) with a maximum height of 90 m (295 ft).
• Bottom-slewing tower cranes: Also known as verti-slewing cranes, they have the slewing mechanism located at the bottom of the tower. Bottom-slewing tower cranes are suitable for various construction projects, especially when there is a need for cranes to be used in confined spaces. The weight capacity of bottom-slewing tower cranes ranges from 2,000 kg to 6,000 kg (4,409 to 13,228 lb) at a maximum height of 60 m (197 ft).
• Flat top tower cranes: They have a flat-topped horizontal mast. Flat-top tower cranes are used on construction projects of various sizes but are most popular on projects where multiple cranes are used at the same time. The lack of a tower head makes it easier for cranes to be assembled closely together and disassembled. Flat-top tower cranes can handle a maximum load of 8,000 kg (17,637 lb) up to a height of 70 m (230 ft).

Specification and maintenance of different types of tower cranes

Specifications

• Capacity: The maximum weight a crane can lift. This can range from a few tons to over 20 tons, depending on the type and size of the tower crane.
• Height: The height of the crane itself, usually measured from the base to the top of the tower. This determines how high it can reach for lifting. Height can range from 30m to over 120m.
• Jib Length: This is the horizontal arm of the crane that extends outwards. The length of the jib determines the working radius of the crane. Jib lengths can range from 30m to 80m or more.
• Working Radius: This is the maximum horizontal distance from the tower (vertical central axis) to where the crane can lift. It depends on the jib length and position. Working radius can range from 30m to over 80m, depending on the crane.
• Rotation: This is the ability of the crane to turn around its base to position loads. Some cranes have 360° continuous rotation, while others have limited rotation.

Maintenance

• Inspection: Carry out regular inspections of the crane to detect any sign of damage or faults early enough.
• Lubrication: Grease all moving parts of the crane, including the bearings, gears, and joints, to avoid unnecessary friction.
• Cleaning: Regularly wash the crane with mild detergent and water to remove dirt and avoid corrosive materials building up.
• Component replacement: Replace worn out or damaged components like tires, ropes, and brakes. Carry out repairs on water damage or any other issues that may arise.
• Electrical system check: Check the wiring system of the crane tower regularly to ensure that there is no loose, worn, or damaged connections. Have all the sensitive electrical components protected from the elements.
• Regularly calibrate the weight sensors and limit switches to ensure they are functioning properly and to avoid accidental overloads.
• Stability checks: Regularly check the stability of the crane, especially if it has been moved from one location to another. Ensure that it is adequately bolted down and that the base is level and solid.

Different types of tower cranes

Tower cranes have become a staple of modernity, symbolizing the world's unending quest for infrastructure and excellence. However, this does not mean the industry has come to a standstill. Innovations in engineering have given us various types of tower cranes, each suited for specific needs and applications.

• Ground-based Tower Crane

  Ground-based tower cranes are the most commonly used type in the construction industry. A ground-based tower crane is anchored directly to the ground of a construction site. It offers great stability and lifting capacity, making it an ideal choice for large-scale projects. Ground-based tower cranes typically have a horizontal arm that is called a jib. The jib of the crane is what loads and releases materials on the construction site. The length of the jib determines how far around the crane can "work." Jibs can either be fixed or movable, depending on the type of crane. Materials are moved around the construction site by rotating the jib horizontally. Vertical movement is achieved by jacking up the crane as the building grows taller. The ground-based tower crane remains a popular choice in tower crane design due to its simple, effective construction method.

• Separator Crane

  A separator crane looks very much like a ground-based tower crane, except that it is mounted on a large, wheeled vehicle. This vehicle moves the separator crane around the site. Its tasks are similar to those of a ground-based tower crane. However, the separator crane is ideal for working in tight spaces, uneven terrain, or when medium- to long-distance transportation is required across the construction site.

• Climber Crane

  Unlike most tower cranes, which are stationary, climber cranes are known for their ability to "climb" or grow taller as the construction project progresses. This is achieved by a self-jacking system that allows it to lower and raise itself on top of the constructed building. Climber cranes have great vertical and horizontal reach. They also offer excellent flexibility and adaptability.

• Topless Crane

  Topless cranes are best suited for large or complex horizontal projects like the construction of bridges or other infrastructural projects over long distances. Topless cranes allow multiple cranes to work simultaneously without colliding into one another. This is because the absence of a head on top of the crane provides for better visibility. The operator of the topless crane can easily see other cranes and contractors on the construction site.

• Fixed Crane

  Fixed cranes are also known as flat-top cranes. Just like the name suggests, fixed top cranes have a flat-shaped top. It is one of the most commonly used tower cranes in the construction industry. Similar to topless cranes, fixed top cranes have no obstructions above the crane. This makes them easier to assemble in tight spaces.

How to choose different types of tower cranes

Business buyers should keep the following factors in mind when choosing a tower crane:

• Project requirements analysis

  Business buyers should analyze their project needs, including the project scale, height requirements, weight of materials, construction period, etc. This analysis will help buyers determine specific parameters of the tower crane, such as its height, lifting capacity, range, etc.

• Selection of Crane types

  Business buyers should choose the appropriate type of tower crane according to project requirements. For example, choose a flat-top tower crane for high-rise projects; choose a luffing jib crane for projects with complex site conditions and short jib range; or select a self-elevating crane for a temporary support system to meet specific project needs.

• Matching of other equipment

  Business buyers should consider the matching of other equipment, such as hoists, scaffolding systems, and material transportation systems, to ensure an efficient construction process.

• Equipment supplier selection

  Business buyers should choose a reputable supplier. Consider the quality, service, and support of the equipment to ensure a reliable choice and long-term equipment support.

• Cost analysis

  Business buyers need to conduct a cost analysis that includes equipment rental or purchase, installation and debugging costs, maintenance and support costs, etc., to ensure that they are making an economical and reasonable choice.

Q&A

Q: What are the key component parts of a tower crane?

A: The main parts of a tower crane include the base, mast, cross arm, jibs, counterjib, hoist, trolley, hook, driving unit, cab, climbing mechanism, and anchor. Each part has a unique function that enables the tower crane to lift and move heavy building materials from one point to another.

Q: How do tower cranes lift and move heavy materials?

A: Tower cranes lift and move heavy construction materials by working like a gigantic trolley. First, the hoist lifts a heavy material with the help of a rope from a hookup point, also called the crane's trolley. Then, the crane rotates the material around its mast, moving it horizontally on its cross arm. Finally, the hoist lowers the material to its proper location. The movement of the crane is controlled from a cab by an operator.

Q: How are tower cranes anchored?

A: Tower cranes are anchored to the building in a vertical manner as construction progresses. Horizontal bracings or concrete diagonals are used to secure the crane in different ways to the structure.

Q: How tall can a tower crane be?

A: A tower crane's height can be increased in a vertical manner by using a climbing mechanism. There is no specific limit to how tall a tower crane can be, but a typical crane can reach a height of 40 meters (or 131 feet) to 65 meters (or 213 feet).