What is the Lifting Capacity of a Tower Crane?

Tower cranes are essential in construction for lifting heavy loads, often at significant heights. Understanding their lifting capacity¹ is crucial for planning safe and efficient operations.

The lifting capacity of a tower crane² depends on various factors, including its design, height, and configuration.

In this article, we'll explore how to calculate a tower crane's lifting capacity, what affects it, and the biggest lifts tower cranes can handle.

How to Calculate SWL³ of Tower Crane?

SWL, or Safe Working Load, is the maximum load a crane can safely lift. Calculating the SWL of a tower crane involves considering several factors such as the crane's model, height, and radius from the crane's center.

The SWL calculation ensures that the crane operates within its safe capacity, preventing accidents or damage to equipment.

To calculate the SWL, follow these general steps:

1. Check the Load Chart: Each crane model comes with a load chart that shows the maximum load it can lift at different boom lengths and operating heights.
2. Determine the Load Radius: This is the distance from the crane’s center to the point where the load is located. The greater the radius, the less weight the crane can lift.
3. Consider the Crane’s Height: As the crane extends higher, its lifting capacity decreases. Ensure you account for the crane's height in the calculation.
4. Account for Environmental Factors: Wind, ground stability, and other site conditions can affect lifting performance.

Example SWL Calculation

Once these factors are considered, you can determine the safe working load from the crane's load chart, ensuring the crane doesn’t exceed its lifting capacity.

What is the Heaviest Tower Crane Lift?

Tower cranes are designed to handle extremely heavy loads. The heaviest lift depends on the crane's specifications and the project's requirements. For example, modern tower cranes can lift thousands of tons, especially when working in industrial projects or large construction sites.

The heaviest lifts tower cranes perform typically involve large structural components, equipment, or materials.

The largest lifts performed by tower cranes often occur on skyscraper projects or large infrastructure developments. Some of the heaviest lifts include:

• Prefabricated building sections: These can weigh hundreds of tons.
• Heavy machinery: Tower cranes are used to lift large equipment, like generators and boilers.
• Wind turbine components: Large cranes are needed to lift turbine blades and towers during wind farm construction.

Some of the heaviest tower cranes, such as the Liebherr LR 13000, have a maximum lifting capacity of 3,000 tons, though such cranes are typically used in specialized industries like energy or large-scale industrial construction.

How Does a Tower Crane Move Up?

A tower crane’s height is adjustable. The process of moving a tower crane upward is called "climbing⁴," and it involves a specific method of extending the crane’s tower section by section.

Tower cranes move up through a climbing mechanism⁵ that adds additional sections to the crane’s mast.

The climbing process generally follows these steps:

1. Installation of a Climbing Frame: A climbing frame is mounted around the crane’s tower.
2. Raising the Mast: A smaller crane, or the crane’s own lifting system, is used to raise the mast and add additional tower sections.
3. Securing the Sections: Once the crane is raised to the desired height, new sections are bolted into place, extending the crane’s vertical reach.
4. Adjusting the Counterweights: To ensure stability, the crane's counterweights are adjusted as the height increases.

This ability to "climb" allows tower cranes to be used in the construction of skyscrapers and other tall structures, where height must be continuously added as the building rises.

What is the Lifting Limit for a Crane?

Every crane, including tower cranes, has a lifting limit known as the maximum lifting capacity⁶. This is the maximum weight a crane can safely lift, depending on various factors such as the crane’s design, boom configuration, and environmental conditions.

The lifting limit for a crane is determined by the crane's manufacturer, as well as by regulatory standards.

The lifting limit for a crane varies depending on the following factors:

• Model of the Crane: Different cranes have different lifting capacities, with larger cranes having higher limits.
• Boom Length⁷: The longer the boom (or arm) of the crane, the lower the lifting capacity, as the load is further from the crane's center of gravity.
• Load Radius⁸: The distance from the crane’s base to the load being lifted also impacts the lifting capacity.

Example Lifting Limits

Lifting limits are designed to ensure the crane can operate safely and avoid tipping or overloading the lifting system.

How Much Can the Average Tower Crane Lift?

The average lifting capacity of a tower crane depends on its model, design, and operational conditions. For standard tower cranes used in construction projects, the typical lifting capacity ranges from 10 tons to 50 tons.

Most tower cranes can lift between 10 and 50 tons, though some specialized cranes can lift much more.

Typical Tower Crane Lifting Capacities

In most cases, tower cranes used for residential or commercial building construction will fall within the 10-30 ton range, with larger cranes used for larger, more demanding projects.

Conclusion

The lifting capacity of a tower crane varies widely, depending on the model and operational factors. Average cranes can lift 10-50 tons, while specialized cranes can handle much more.