If you’re enjoying the perks of condo living, you may also be curious about how your condominium came to be. Cranes are mainly responsible for why you’re able to have a home on the 15th floor and delight in a spectacular view. With cranes, the construction of tall buildings like those housing condominiums has become easy and safe.
In building a multi-level structure, a tower crane is the most important equipment. Similar to how you move large items in your house, a crate lifts heavy materials like concrete slabs, steel structure and various machinery. With the huge volume of tasks that this equipment can do, it ensures maximum productivity in every construction project.
Types of Cranes
Below are four common types of cranes you can find in some of today’s construction sites.
This is mainly used in the construction of high buildings. They are set to the ground during the construction process to stay securely in place even when lifting heavy weights.
Rough Terrain Crane
This is a special type of truck-mounted crane which works for off-road applications.
Most people refer to this as a “sky crane” since they’re helicopters which mainly function to lift heavy loads. This crane is quite useful when conventional cranes are out of the question. This is also helpful during risk relief operations and disaster mitigation.
Vehicle Mounted Crane
This is a type of crane which is set on a vehicle for mobility. With this, there’s no longer a need to hire additional equipment to transport the crane.
A crane usually consists of the following parts:
1. Tower or Mast
The base of a crane connects to a tower or mast which gives its height. This tower has guard and guide rails which direct the elevator. This elevator ensures the maintenance technician and operator reach the machinery arm and operator’s cab.
This is responsible for the interface between the building top and steel structure. It functions like the spine supporting the human body.
3. Slewing Unit
This is the tower crane’s mobile part. It’s capable of a 360-degree rotation and has a combination of motors and gears that enable the crane to swing.
4. Machine House
You can see this along the line of the jib and usually extends at the back of the crane’s center. It houses the motor and other electronic parts necessary for crane operations.
- Incorporates all safety devices
- Eliminates water access and withstands heavy winds
- Integrates huge concrete counterweights which provide balance while lifting
5. Long Horizontal Jib
It functions as the working arm of the crane. It had the ability to extend horizontally, transporting a trolley that runs to and from the crane’s center.
6. Operator’s Cabin
This is where the operator controls the crane. It’s found where none of the crane operations can hinder the operator’s visibility.
How much weight can a crane handle?
The maximum weight load that a crane can handle is 39,690 pounds or 18 metric tons. But it can’t lift as much weight when the load is at the end of the jib. The closer the load is to the mast, the more weight it can lift safely.
For a typical tower crane, the following are the specifications.
- Maximum Reach – 70 meters or 230 feet
- Maximum Lifting Power – 18 metric tons or 19.8 tons
- Counterweights – 16.3 metric tons or 20 tons
- Maximum Unsupported Height – 80 meters or 265 feet. The crane can have a height greater than 265 feet when fixed to a building.
Similar to emergency devices at home, a crane has the following limit switches to make sure the operator doesn’t weigh down the crane.
- Maximum Load Switch – It monitors the cable pulling and ensures that the load doesn’t go beyond 18 tons.
- Load Moment Switch – It makes sure that the operator doesn’t go beyond the ton-meter rating while the load moves out from the jib.
What keeps a crane standing upright?
When looking at a tower crane, the structure seems outrageous. You begin to wonder why it doesn’t fall over when it has no support wires. The secret to a crane’s stability is a huge concrete pad. Construction companies embed large anchor bolts deep into the concrete pad to support the crane base.
How does it extend?
A tower crane comes in a construction site on tractor-trailer rigs. A crew will then use a mobile crane to assemble the jib and machinery section. To reach its maximum height, the crane crows one mast section at a time.
Below are details of the process:
- The crew hangs a weight on the jib in order to balance the counterweight.
- The crew detaches the slewing unit from the mast.
- The large hydraulic rams on the top climber pushing the slewing unit up to 6 meters or 20 feet.
- The crane operator uses the crane to carry another 20-foot mast section into the climbing frame gap. Once it is securely in place, the crane will be 20 feet taller.
When the construction of the building is finished, the crane then comes down. It disassembles its own mast and the smaller cranes strip down the rest.
It’s pretty hard to miss a crane because it is highly visible up in the air. Now that you are aware of this powerful equipment, you no longer have to wonder how a tall building grows to such heights. The next time you pass by a construction site, observe how a crane works to witness it doing its many jobs firsthand.
Hermann Buchberger is the Founder and CEO of Active Crane Hire (ACH). He’s taken the company from start-up to Industry Leader offering the largest fleet of construction cranes in Australia. ACH launched a new type of crane previously unheard of in the Australian market: electric tower cranes. The company’s infrastructure and associated services now comprise a fleet of trucks and trailers, a crane-rigging team, mobile crane technicians, a fleet of service vehicles, and an extensive range of crane spare parts.