It would be all but impossible (and certainly inefficient) to build bridges, high-rises, roads, or any other large project without construction cranes. They are used to raise or lower heavy objects, transport objects around the construction site, and are essential for the building or deconstructing large structures.
Many different types of cranes have been developed to meet specific needs of given projects, because they are vital to building so many different structures. A crawler cranes will be different depending on the kind of lift it’s designed to execute. This guide will introduce a few of the many kinds of construction cranes available and a bit about which type of project they are most helpful for.
Static cranes and mobile cranes
The many types of construction cranes can be broken down into two basic categories: static and mobile.
- These cranes are to be used in a single space and move things along a predetermined path.
- They are frequently attached to the roof or side of a structure.
- They can also be anchored directly to the ground.
- In any case, these are designed to stay in a single spot for the duration of construction.
- As the name implies, these cranes are designed to move about the jobsite during a construction project.
- These are intended to be used to move things from one place to another quickly and easily.
What Are Static Cranes?
Static cranes are used mostly for long-term construction projects or are intended to be permanently installed on a jobsite.
- Are designed to lift and move heavy loads along a preset path
- Are designed to accomplish pre-planned tasks
- Perform the task they are designed for very well but offer little flexibility on the job.
- There are several types of static construction cranes, each designed to meet different needs.
- Tower cranes are perhaps the most widely recognized type of crane for construction, if for no other reason than they are hard to miss. Often quite large, their crane towers stand tall in the middle of construction sites for all the world to see.
Tower cranes are made up of the tower, or mast, and the jib, the arm that extends out from the mast. The jib can move a full 360° around the mast, with a trolley that runs up and down the full length of the jib, allowing the block hook to be lowered to the correct location.
Static cranes are the type most often used to build large structures over a longer timeline. They’re commonly used in urban areas where space is limited and the public is rarely far away. Their stability provides an extra layer of safety for both those who work at the sight and those outside the fencing.
They are powerful and capable of lifting large weights very high if necessary, but they are limited to a single area. While they do extend and rotate, there is still a limit to their range of motion.
There are three primary types of tower cranes, including:
- Hammerhead cranes
- Luffing tower cranes
- Self-erecting tower cranes
Hammerhead cranes resemble an upside-down L, with the jib remaining at a set level. The jib can usually rotate but cannot be raised or lowered. This model is frequently found on loading docks where many cranes may be operating simultaneously at various levels. They are also used in situations where space may be limited, like inside a structure or at particularly tight construction sites.
There are two basic designs for tower cranes: the A-frame, and the flat top.
- Uses a metal structure to connect cables from the jib to the counter jib, a short but has a heavily weighted structure behind the jib
- This is used for leverage and allows this type of tower crane to lift heavier weights.
- Has no additional structures above the tower and is used for lifting lighter weights
Luffing Jib Crane
- The luffing jib type of tower crane is very similar in structure to the hammerhead but has one major difference. The jib can be raised and lowered on luffing jib construction cranes. This design gives them added flexibility while allowing them to lift heavier weights.
- The luffing crane is more expensive than the hammerhead, but can be more efficient with a smaller rotation radius, allowing it to be used in tighter construction sites. It can also be used where multiple cranes are operating at the same time.
- Relatively speaking, the self-erecting cranes are the lightweights of the static crane family. They are designed to be easily set up and dismantled.
Self-erecting cranes are ideal for working in tight spaces or for shorter-term construction jobs. Their major shortcoming, however, is that they cannot lift as much weight as the other types of tower cranes.
Level Luffing Cranes
Similar in appearance and function to the tower luffing cranes, the level luffing cranes have one major difference — they do not have trolleys that run along the jib. Instead, the hook block is fixed at the end of the jib, and the jib itself moves up and down to move the load. This design allows the load to stay level while being lifted.
This type of construction crane is most often used for shipbuilding and loading and unloading freight.