Construction cranes are powerful machines capable of lifting heavy loads.
The history of construction cranes dates back to 515 BC when the Greeks invented them to lift materials during the construction of the Greek temple.
Ever since their invention, different types of cranes have evolved in terms of designs and capabilities, thereby becoming a common feature in large construction projects.
What are the two main types of cranes?
There are two main types of cranes: mobile cranes and static cranes.
A mobile crane is typically mounted on wheels or treads and can be moved from one site to another. A static crane is fixed to the ground or building to move loads along a fixed path.
The two types of cranes are subcategorized as follows: –
As the name suggests, these cranes are mounted on trucks. They consist of a carrier (truck) and a boom (arm) and are only moved to a construction site when needed.
Truck-mounted cranes. PHOTO | FILETruck-mounted cranes are fitted with outriggers for stabilizing the crane while working on site. They are mostly used for inspection, maintenance, and construction of bridges.
Crawler cranes are specially designed for heavy-load transportation at a construction site. Instead of wheels, crawlers are built on an undercarriage fitted with a pair of rubber tracks.
Though this design limits the crawler’s turning capacity, it helps the machine operate on soft soils without the risk of sinking.
Crawler cranes at work. PHOTO | FILESome crawler cranes come with a telescopic arm that allows for an increase or reduction in size, which enhances their ability to operate in various terrains.
Due to their huge sizes, these construction cranes are ideal for long-term projects.
All-terrain cranes are designed to operate on both paved roads and rough terrain.
They are fitted with more wheels than standard vehicles for stability and to prevent overturning in rugged terrains.
All-terrain crane. PHOTO | FILEAll-terrain cranes are often used instead of rugged terrain cranes and vehicle-mounted cranes to perform dual-purpose tasks.
Rough terrain cranes are designed to operate in rough territories where ordinary truck-mounted cranes are not feasible.
They are built like crawler cranes and fitted with four rubber tyres instead of tracks.
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Rough terrain cranes are fitted with telescopic booms and outriggers to enhance stability and allow easier maneuvering in tight and rough areas.
Rough terrain crane. PHOTO | FILECarry deck cranes are an evolution of the pick-and-carry model that first came into use in the 1980s. These are small, four-wheeled machines that can rotate a full 360 degrees, allowing them to navigate around confined and open spaces.
Carry deck crane. PHOTO | FILECarry deck cranes are ideal for lifting loads that require compact, low-profile cranes that can simultaneously maneuver in very tight spaces while clearing overhead obstacles.
Also known as flying cranes, aerial cranes are special types of helicopters used to lift loads in areas that are inaccessible by land, such as rooftops of skyscrapers, or sites away from roads.
Aerial cranes use long cables or slings to lift loads in an operation known as ‘longline,’ owing to the length of the cable used for carrying the load.
Aerial crane. PHOTO | FILEAerial cranes came into use in the 1950s, but it was not until the 1960s that their usage took off in the construction industry. This was after the more powerful Sikorsky S-58 helicopters replaced the Bell 47, allowing the lifting of heavier loads.
As the name suggests, floating cranes are positioned on the sea and used for the construction of ports and oil rigs. They operate like other construction cranes, except that they are used at sea.
Floating cranes. PHOTO | FILEFloating cranes have an enormous lifting capacity, which makes them useful for retrieving sunken ships from the water. As of 2019, the world’s largest floating crane was Lanjing, owned by China National Offshore Oil Corporation through its subsidiary CNOOC.
Tower cranes are powerful lifting machines fixed to the ground during the construction of skyscrapers. Typical tower cranes have a maximum unsupported height of 80 meters or higher if tied into the building as the structure rises around the crane.
A standard tower crane has a lifting capacity of 20 tons.
Tower crane. PHOTO | FILETower cranes are built along with a building and rise alongside it. They are fitted to a strong concrete base and anchored by large bolts that are easily removed after the work.
This is a heavy-duty crane with a horizontal jib that rotates a full 360 degrees around a mast at a fixed level and a structure that resembles an upside-down “L.”
Hammerhead tower crane. PHOTO | FILEHammerhead tower cranes are adapted for any job site lifting task and are reliable for accurate handling of loads.
These types of construction cranes can be exceedingly heavy and are assembled on site.
Luffing tower crane, also called a luffing-jib crane, is designed like a hammerhead tower crane except that the jib is interlaced and can be elevated or dropped in a motion known as luffing.
Luffing tower crane. PHOTO | COURTESYThese types of cranes have the capacity to lift heavier loads than hammerhead tower cranes. They are ideal for congested sites or those with multiple cranes due to their small swinging radius.
Self-erecting tower cranes are lightweight cranes that have a horizontal jib and a mast mounted to a ballast.
They are designed to fold and unfold to allow their erection and dismantling on site.
Self-erecting tower crane. PHOTO | COURTESYUnlike the above two types of tower cranes, self-erecting tower cranes have a much lower maximum load capacity, making them ideal for sites that do not require heavyduty cranes and those with frequent erection and dismantling of equipment.
Telescopic cranes are equipped with a large boom (arm) in which several hydraulic cylinders are fitted, one inside the other, allowing the boom to grow or shrink like a telescope.
Telescopic crane. PHOTO | FILEMost telescopic cranes are mounted on tracks to allow movement to and from different sites. This makes them ideal for short-term construction jobs, such as the installation of signal masts.
A telescopic handler crane is a forklift-like machine that is fitted with a boom (telescopic cylinder) that extends forward and upward from the vehicle. This makes it ideal for handling tasks such as installation of steel trusses on tall buildings.
Telescopic handler crane. PHOTO | FILEA bulk handling crane is designed with an integral grab that enables it to lift bulk loads.
Bulk handling crane. PHOTO | FILEWhile most bulk handling cranes are dedicated to a single product, some cranes are fitted with several grabs to efficiently handle large volumes of diverse materials.
Overhead cranes are permanent structures installed on site to perform repetitive tasks. They have a horizontal beam that moves horizontally up and down a runway above a site.
Overhead crane. PHOTO | COURTESYA trolley and hoist travel from one side to the other along the bridge beam to lift and lower loads throughout a rectangular bay. They are used to enhance safety and efficiency within a site.
A gantry crane is a type of overhead crane with a single or double beam formation supported by two A-frame steel legs that move on a track to carry loads from one area to another.
Gantry crane. PHOTO | FILEThey are mainly used in projects that do not require an overhead runway system for the crane’s movement.
A jib crane is a hoist with a jib arm (horizontal beam) that is typically mounted on either a wall or floor-mounted pillar with a movable hoist that lifts, positions, or lowers a load.
Jib crane. PHOTO | FILEThese types of cranes are often used on smaller jobsites for repetitive lifting operations.