Cranes are machines that lift and carry items that are too heavy for people, to places that those people aren’t physically able to carry them.
Types of cranes
Because there are so many industries that have their own requirements and methods of lifting, there needs to be an array of crane styles and categories to cater for them. There are different types of cranes, including static cranes, stationary cranes, fixed cranes, versatile cranes, and mobile construction cranes. Selecting the most suitable crane for each construction project is essential to ensure efficiency, safety, and cost-effectiveness.
There are sixteen main crane types, representing the different types of cranes used across various industries. Each of which are unique to specific fields.
Here are some of the most common crane categories that are used in construction:
Tower cranes
There are various types of tower cranes. The main ones used in construction are Self-Erecting Cranes, otherwise known as Pedestrian Operated Tower Cranes (Ped-ops); luffing jibs (luffers), and saddle jibs, otherwise known as flat-tops or saddlebacks. Among these, hammerhead cranes (also known as hammerhead crane) and balance cranes are important subtypes, recognized for their impressive lifting capability and ability to lift heavy loads in urban construction projects. You can learn the difference between luffing jibs and saddle jibs here.
Crawler cranes
Crawler cranes are tracked machines. Some of which are capable of lifting very heavy loads. They are especially suitable for operating on rough terrains, making them ideal for challenging job sites where they need to lift heavy loads and lift heavy materials. They generally have lattice booms, of which can accommodate jib extensions if needed. But some have telescopic booms. Crawler cranes get transported to site and built on arrival.
Wheeled telescopic cranes
Wheeled telescopic cranes are more commonly known as mobile cranes. They get driven to site, therefore, operators using them need an HGV license as well as their crane license.
Common types of mobile cranes include truck cranes, truck crane, boom truck, truck mounted crane, loader cranes, and carry deck crane. These cranes are valued for their mobility and versatility, allowing them to handle a wide range of lifting tasks across different industries and locations.
The beauty of mobile cranes is in the name. Because they are so easily transportable, they can be hired for ad hoc lifts, not only in construction but on busy streets, by companies or for domestic use. They’re also often used on wind farms. A telescopic crane, for example, features an extendable boom that can be hydraulically extended and retracted, making it highly adaptable for various tasks such as construction, rescue operations, and transportation.
How do cranes work?
First, for cranes to work, they need a power source, whether it’s electricity from generators or the main grid, or diesel. Some cranes are now even battery powered.
Historically, cranes operated using a manual pulley system, which was the original method for lifting materials vertically. Over time, crane technology evolved, and modern cranes now utilize electric motors and hydraulic power, offering greater efficiency, emission-free operation, and suitability for indoor environments.
Cranes work using the age-old system of pulleys and counterbalancing. Steel cable, that is wrapped around a drum attached to a winch, travels through a series of pulleys and sheeves to help increase the lifting capacity. The more pulleys there are, the more weight the crane can lift. In telescopic cranes, a hydraulic cylinder within the boom enables extension and retraction, making these cranes highly versatile. Advancements in crane technology, such as improved hydraulic systems and electric motors, have significantly enhanced lifting mechanisms and operational capabilities.
Counterweights at the back of cranes counteract the weight that gets lifted at the front. This helps to prevent the crane from tipping over.
Parts of a crane
Crane parts vary, depending on the type of crane. But the main parts are as follows.
- Lifting mechanism (enables vertical movement and heavy lifting)
- Crane hook (used for precise material handling, especially in level-luffing cranes)
- Hook
- Slew ring
- Boom/jib
- Counterweight
Cranes are a type of lifting equipment commonly used in construction and industry.
Hook
Crane hooks, also known as the crane hook, are essential components in lifting operations, hanging from jibs/booms using hoist rope. Loads and lifting accessories attach to the hooks for lifting.
Slew ring
Crane slew rings are the central part of cranes that help them rotate 360°. They’re also known as turntables.
Counterweight
As stated previously, to keep cranes stable, counterweights at the back counteract weight being lifted at the front. The weight of the counterweights should be greater than the crane’s lifting capacity. Because of this and built in sensors, when cranes do tip over it is usually down to operator error. Cranes that travel on the ground are more likely to tip over than tower cranes, because most tower cranes are anchored into the ground using large bases.
How are tower cranes built?
To most people, quite how tower cranes spring up in city skylines is quite the mystery. Well, it takes a lot of planning, logistics, and teamwork.
The process to building tower cranes goes in these stages:
- Planning
- Base build
- Erecting crane
- Test and sign off
Planning
Engineers, operation managers, and appointed persons (APs) decide what size cranes are going in which locations. The weights of the heaviest loads throughout the project must be predetermined to ensure each crane is sufficient enough to lift them. Also, each crane must have enough reach to cover the majority of the project.
In some cases, various authorities must be notified when a crane is to be erected, such as Network Rail (if the crane will be close to a rail line) and the Civil Aviation Authority (CAA).
The crane must be high enough to clear the structure that it’s due to build. And if it is due to be 100m Above Ground Level (AGL), the CAA must be notified. They must also be notified if crane is to be erected within 6km of aerodromes or airfields, and 10m AGL or surrounding trees or structures, if higher.
Base build
Crane bases are designed and built in relation to elements like ground or existing platform conditions, crane type and size, and local wind speeds.
The types of bases for tower cranes are:
- Piled-foundation bases
- Gravity bases
- Grillages
- Ballasted cruciform bases
This article provides you with a thorough understanding of crane bases.
Erecting the crane
Tower cranes get erected by specialist teams of crane erectors, usually over weekends when sites are not busy, and road closures, if needed, are more attainable. Mobile cranes or other tower cranes are used to lift the crane parts.
Erection procedures and the order of these procedures vary depending on the teams carrying out the work, as well as crane manufacturer guidelines. But here is a simple breakdown of the general erection process.
- Once the crane base is built, a tower section gets anchored to the base. Then other tower sections are added and bolted on top each other until the desired height is reached.
- For extra stability, if a crane is to go too high to be freestanding, tie bars connect the mast to a structure. These get installed at certain intervals.
- If a crane is to eventually be climbed higher to match the full building height, a climbing frame is sometimes installed ready. But this can also be done at a later date.
- A slew ring gets bolted to the top of the tower. This allows the crane to rotate 360 degrees.
- The crane operator’s cab gets attached.
- The counter-jib (or back-jib) gets installed.
- If not preinstalled, winches and electrical panels are placed on the back-jib.
- The main jib gets attached to the front. This is where the crane’s lifting work gets done.
- Ballast weights (counterweights) get installed at the rear to balance the crane out.
Test and sign off
Once a tower crane is built, all the functions get tested to make sure it is fully operational. Then, the crane lifts a test weight to calibrate the scales and ensure it can lift to its full capacity.
Before the crane can be put to work, it must undergo a LOLER thorough inspection. This gets done prior to use on any lifting machinery assembled on site. This inspection gets repeated annually to certify the crane.
Crane Applications
Cranes play a crucial role in a wide variety of industries, serving as indispensable tools for lifting, moving, and positioning heavy materials and equipment. Their versatility and impressive lifting capacity make them essential for everything from constructing tall buildings to handling cargo at busy ports.
In the construction industry, cranes are at the heart of major projects. Tower cranes dominate urban construction sites, enabling teams to construct tall buildings and skyscrapers by lifting steel beams, concrete panels, and other heavy materials to great heights. Mobile cranes, including truck mounted cranes and rough terrain cranes, are valued for their ability to move quickly between job sites and handle a range of lifting operations, from setting precast concrete to supporting demolition work. Crawler cranes, with their tracked undercarriage, are especially useful on construction sites with soft or uneven ground, providing stability and the ability to lift heavier loads.
Gantry cranes and overhead cranes are widely used in environments where heavy lifting is a daily requirement. Gantry cranes, often seen in shipyards and large construction sites, can straddle large objects and move them efficiently across container yards or assembly areas. Overhead cranes, also known as bridge cranes, are a staple in factories and warehouses, where they move heavy equipment and materials along a fixed path, maximizing floor space and streamlining production processes. Jib cranes, with their rotating jib arm, are ideal for workshops and smaller spaces, offering precise control for lifting lighter loads.
Truck mounted cranes, or boom trucks, combine mobility with lifting power, making them perfect for construction sites, container yards, and infrastructure projects where equipment needs to be transported and set up quickly. Their truck chassis allows them to travel on public roads, reducing setup time and increasing efficiency. Telescopic cranes, featuring a telescopic boom, are highly adaptable and can extend their reach to access difficult or elevated locations, making them invaluable for both construction and emergency response scenarios.
Carry deck cranes are compact and maneuverable, designed for lifting operations in tight spaces or on congested job sites. Their ability to rotate the boom 360 degrees and carry loads on their deck makes them a popular choice for industrial maintenance and plant work. Floating cranes, mounted on barges or ships, are essential for marine construction projects, such as building bridges, unloading containers, or supporting offshore installations where traditional cranes cannot operate.
Beyond construction, cranes are vital in manufacturing, mining, oil and gas, and renewable energy sectors. They are used to assemble heavy machinery, move large components, and support the installation and maintenance of wind turbines and other infrastructure. Deck cranes are commonly found on ships, handling cargo during loading and unloading operations at ports and harbors.
The use of cranes brings significant benefits to any project. They increase efficiency by enabling the rapid movement of heavy materials, boost productivity by reducing manual labor, and enhance safety by minimizing the risk of injury during lifting operations. Cranes also offer precise control, allowing operators to position loads exactly where needed, which is critical for complex lifting tasks and the construction of intricate structures.
As industries continue to evolve, the applications for cranes expand as well. Modern cranes are designed to adapt to a wide range of environments, from indoor manufacturing plants to rugged outdoor construction sites. Whether it’s a tower crane reaching into the skyline, a gantry crane straddling massive ship components, or a mobile crane navigating urban streets, these machines are at the forefront of lifting technology, making it possible to achieve complex lifting tasks safely and efficiently.
In summary, cranes are an essential part of modern industry, supporting construction projects, manufacturing, transportation, and more. Their high lifting capacity, versatility, and precision make them the right crane for countless applications, ensuring that heavy lifting is done safely, quickly, and with minimal risk—no matter the job site or challenge.
