In many major cities like the Gold Coast and Brisbane, cranes are as much a part of the skyline as tall buildings. But have you ever wondered how a tall, skinny crane managed to get on top of a building hundreds of metres high?
These cranes are called tower cranes. Tower cranes have a concrete slab for a base which is fixed to the floor or sides of the building. At the top of the crane is a slewing unit which allows it to rotate using a gear and motor. Using all these components, a tower crane can hoist itself up level by level.
Assembling a Tower Crane
To assemble the initial tower crane, it needs to be built using smaller, mobile cranes. These cranes are mounted on the back of trucks and usually use a hydraulic system to lift heavy loads like concrete pillars and steel beams. These crane trucks transport all the necessary equipment to the site and assemble the jib (the long horizontal arm), machinery and counter-weight to complete the tower crane.
Once complete, the crane base is gradually raised up as the skyscraper itself is getting built. This is achieved using a top climber or climbing frame, which fits between the top of the tower and the slewing unit. The slewing unit is detached from the top of the mast, and a hydraulic machine in the top climber pushes the slewing unit up. The crane then lifts itself up another mast section into the gap opened by the climbing frame and is then bolted into place.
Benefits of the External Raising Method
The external raising method is one of the best ways of utilising a tower crane when constructing a tall building, as it allows construction to resume inside the building without halting the progress of each floor. As each floor is constructed, struts are used to raise the base of the crane, allowing it to reach the last few sections at the top of a building.
This minimises downtime, especially when the crane needs to be taken down from its anchor points. When the crane is raised inside the building itself, each floor needs to be constructed before raising it. Rather than using a helicopter or another crane to remove parts, the external crane method allows the crane to be moved back down the side of a building and to place itself back on its ground anchor.
Mobile Crane Hire – Gold Coast and Brisbane
Do you need to hire a mobile crane to build a tower crane or for any other domestic or commercial job? Surf City Cranes offer a variety of quality cranes and manitous for hire on the Gold Coast, Brisbane, Northern NSW and Ipswich. Ask our friendly experts about our different cranes and their capabilities and accessories. Call us today on 1300 444 737 or 0402 269 535 or contact us online.