To the Skies: What Is A Tower Crane and How Does It Work?

Anyone who has been in a major city or near a large construction site has probably seen tower cranes at work, but they may not have stopped to consider how different the world would be without them. 

Tower cranes trace their origins back to the early 20th century, when the first mobile, quick-assembly tower crane was created.

Whether you’re building an industrial complex, a hydroelectric dam, or a multistory apartment complex, many projects today depend on tower cranes to do the heavy lifting for them. That’s why you need to know what goes into tower cranes, how they work, and what your options are for your site — and it’s why you may want to consider a tower crane rental to make sure your operation goes smoothly. 

What Are Tower Cranes? 

Tower cranes are best known for their lofty, skeletal trusses that loom over the top of high-rise construction sites, but tower cranes have several operational features that set them apart from other heavy lifters. Perhaps most noteworthy, unlike mobile cranes such as crawler cranes, tower cranes are stationary and are either fixed to a foundation on the ground next to a building or mounted onto the structure itself.

Parts of a Tower Crane

Another distinguishing feature of tower cranes is the number of components used to build them. The most important tower crane components are:

• The base support, which fixes the crane in place and bears the brunt of the load
• The tower or mast, which is the vertical part of the crane that gives the machine its height
• The tie-ins, which support the crane by attaching it to the structure being built when exceptionally high lift heights are required
• The slewing unit, which is the gear and motor assembly that sits atop the mast, enabling it to rotate
• The turntable, which is the platform that turns the horizontal arm of the crane
• The cab, which houses the operator
• The jib, which is the horizontal arm that stretches over the load
• The counter jib, which sticks out from the back of the crane and contains the counterweights
• The hook and trolley assembly, which links the jib to the load and moves it to its destination through a series of pulleys

With so many parts, it’s no wonder that erecting a tower crane is often considered an entire subsystem within the larger build. That’s why many companies prefer to rent, so that they can focus on the rest of the project and leave the heavy lifting to the crane rental provider.

How Do Tower Cranes Work?

Understanding how tower cranes are operated can help ensure a successful project and mitigate any risks of failure. There’s much more to tower crane operation than this, but here’s a look at the basics:

1. The base support for the tower crane is laid first, fixing it firmly in place. This is usually done by pouring a concrete foundation at the project site or by mounting the crane onto a nearby structure — often the very building it’s helping to erect.
2. The mast is assembled by attaching segments of steel trusses to one another until the tower reaches its desired height. As the project rises higher and higher, the crane must often rise with it, so it’s common to find self-climbing tower cranes that add extra links of trusses to the mast so that they can grow along with the build.
3. After the tower is built, the slewing unit, turntable, and cab are attached, allowing the crane to rotate a full 360 degrees and to be maneuvered by an operator — though it typically takes a team.
4. The jib, counter jib, and counterweights are attached next. The jib gives the tower crane its reach, while the counter jib and weights provide stabilization so that the crane won’t topple under its load.
5. The hook and trolley are attached to the jib and mast, usually as a system of pulleys. This lets the hook drop down to reach the load and enables the crane to hoist it to its destination.
6. For exceptionally tall projects, the crane can be tied-in to the structure and then climbed to greater heights than would otherwise be allowable for a freestanding crane.
7. Once the project is completed, the tower crane is disassembled in the reverse order from which it was built.

That’s a general outline of how tower cranes are operated, but many other factors must be considered when you plan out your tower crane project, including the following:

• Lifting capacity: can range from a ton to hundreds of tons — so be sure to consult the load charts for your crane before attempting a lift
• Crane type: hammerhead, luffing jib, or self-erecting
• Sourcing agreements: purchase, bare rental, or operated and maintained
• Worksite requirements: available space, environmental regulations, and more

There are certainly plenty of variables to account for when you select a tower crane, and while your team may be able to pull it off, you’ll likely find it more efficient to contact an established rental crane supplier that can  help you decide on the right crane for your project. 

Maxim Crane: Your Tower Crane Provider

From power plants and dams to high-rises and hospitals, tower cranes are essential for any building project that aims to reach toward the sky. Without tower cranes, the buildings that dot our cities’ skylines wouldn’t exist. 

Maxim Crane not only has a fleet of tower cranes that are sure to meet your project’s requirements, but our experienced team of engineers can also walk you through the process of planning out your lifts and choosing the crane that’s right for you. 

We also have a range of sourcing agreements, like bare rental or operated and maintained, so that our clients can decide how much assistance they need.If your project is in need of a heavy lifter to get it off the ground, check out our tower crane rental options, and we’ll help your site rise to new heights.