The question of why and when to choose a luffing crane over a hammerhead or flat top has come up a lot in recent meetings. I thought it appropriate to touch on some of the key concepts to consider when choosing the tower crane setup model for your next project. I’ll review a few pros and cons of using a luffing crane and hope you can use this as useful guide.
Luffing cranes, especially over the last 15 years, have helped to solve a lot of inner city construction problems when it comes to the fight for precious space in and around a construction site. With the design of the luffing crane, the jib has the capability of being lift standing vertical in the air at a minimum of 5m radius from the mass section. This is the opposite to the flat top crane which must be left parallel to the project and at the fixed radius of the jib already pre-determined.
This has solved a lot of issues for projects where over sailing rights are not possible or very difficult to achieve in cities around the world. These rights are not usually given when the loads being carried by the crane must be brought overtop of neighbouring building which are public, government or have a heavy population of the general public such as public transport stations. The luffing crane allows the jib and the load to stay within the construction site boundaries at all times and ensure the safety of the general public.
Although luffing cranes are life savers when it comes to working within major city centres or enclosed construction sites they can greatly affect performance and economics of a construction site not hindered by tight jurisdictions.
The major impact these cranes have on a construction site is the time that it takes for them to perform movements necessary to lift an object from point A to point B. The Luffing crane must perform more movements mechanically in order to raise the object to the desired height and radius.
A flat top crane has a fixed jib set to a pre-determined radius, in order for them to perform a lift they must simply reel in the rope to lift the object to the desired height and move a trolley down a track in order to move the object to the desired radius.
With a luffing crane you do not have the trolley moving quickly down a track, instead you must lift the entire jib using an ‘A’ frame positioned at the rear of the crane top and move it up and down until you have reached your desired radius, while at the same time reeling in the ropes to gain the appropriate height for your load. This takes a lot more time to perform these tasks and can be much more difficult especially if the driver is working blind and is not able to see the load at the end of their ropes.
In conclusion the luffing crane, like all other tower cranes, has its pros and cons so when you are designing your site you must ensure that it is the right crane for the job. In tight construction zones such as inner cities a luffing crane may be your best call. If you make the wrong choice you will find as a result that there is a lot of time and money wasted on the project.
What has been your experience in using a luffing crane?
For more about luffing cranes or if you need guidance for your next project, contact me today.