You’ve probably seen enormous cranes posted on or near tall buildings. But how did they get there? What you saw was a tower crane, and it’s put together on a work site. First, it arrives at the work site via multiple tractor-trailer rigs. Then a crew will begin assembling parts with a mobile crane. Tower cranes sit in a fixed position as they work and stay there until the job is done. Then it’ll be disassembled and transferred off-site. This blog will give an in-depth look into how tower cranes grow.
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What Are Tower Cranes?
Every high-rise or skyscraper was constructed using tower cranes. They are the most powerful type of crane. To lift heavy objects and swing them around without falling over, tower cranes are anchored down by a concrete slab. The base of the crane is bolted down to the ground to maintain a fixed position. If necessary, supports can be attached to the building to increase the height and strength of the tower crane.
Parts of a Crane
- Concrete Pad – The concrete slab allows the base of the tower crane to stand strong in a fixed position. It can span 30 feet by 30 feet range and weighs about 400,000 pounds.
- Mast – The mast is a tower that can reach around 265 feet or higher and is typically made of steel trusses.
- Slewing Unit – The slewing is a mechanical component at the top of the mast that allows the crane to rotate.
- Jib – The long arm extending from the crane is called the jib.
- Machinery Arm – The machinery arm is the shorter arm containing the counterweight that allows the cranes to balance their heavy loads. You’ll see it opposite of the jib.
- Operator’s Cab – You’ll find the controls and several safety mechanisms in the operator’s cab.
How Are Tower Cranes Put Together for Construction Sites?
Once the parts of the crane arrive, the crew will go through these steps to safely grow the tower crane.
Step 1: Lay The Foundation
At the bottom of the tower crane is a massive concrete slab. Before the crane can be fixed into position, the crew will lay the concrete pad. The crew will also erect the first section of the crane’s vertical pole inside the pad. The concrete pad is vital to the crane’s strength and stability. All forces that come with lifting, swinging, and rotating heavy materials must be accounted for when constructing the pad.
A mobile crane will get the initial pieces and core components assembled. Piece by piece, the mobile crane will grow the tower crane up to a predetermined height. Once it reaches that point, the mobile crane will attach other critical components to the tower crane. These include the jib, counter jib, cab, turntable, and engine. From there, the tower crane can grow itself if it needs to reach greater heights. Here’s how it does it:
- A climbing unit from the base is built and lifted to the top.
- The new piece is raised by the hook, which moves via a trolley to attach to the climbing unit.
- A hydraulic jack creates a space for the new tower piece, which is fastened to the tower.
Step 3: The Tower Crane Grows Itself
As more pieces are added, the tower crane will continue growing itself until the predetermined height is reached. Counterweights are used to keep the tower balanced as it’s assembled, which helps prevent tipping.
How Much Weight Can They Lift?
You don’t know power until you’ve seen a tower crane in action. A tower crane’s lifting capacity could reach up to 18 metric tons. However, it cannot handle that much weight if the load is positioned at the end of the jib. When the load is positioned close to the mast, the crane can handle heavier weights safely. Here is how you can find the capacity limit at a certain position. Using the 300-tonne-meter rating, you can calculate that a load at 30 meters (100 feet) from the mast means the crane can lift a maximum of 10.1 tonnes.
Why Don’t They Fall Over?
Wondering how tower cranes can be so tall and so powerful without tipping or collapsing? Just like the building they’re constructing, a tower crane draws its stability from its foundation. In this case, the foundation is a 400,000 pounds concrete pad. The base of the crane is bolted down to the pad, keeping the tower stable throughout the operation.
Want to Become a Tower Crane Operator?
Thinking about becoming a tower crane operator? Then there are a few things you need to do first. First, you need training and certification. Tower cranes are powerful machines, but one mistake could spell disaster. You can learn all about the parts of a crane, safety procedures, and other important information in a heavy equipment operator training program.
Where Can You Find the Best Tower Crane School?
Deciding to go back to school or continue your education can seem like an uphill battle, but choosing the right program for you will make all the difference. The best programs will offer you accelerated paths to entering the job market with the right credentials and training. They’ll also assist you beyond the classroom through career services.
Heavy Equipment Programs at Heavy Equipment Colleges of America (HEC)
Ready to start your career as a tower crane operator? HEC has a tower crane program that you can complete in as little as two weeks. You’ll gain hands-on experience and learn from experienced instructors as you prepare for certification. Once you’ve completed the program, you’ll have access to career services like resume writing, mock interviews, and more.
HEC also has other heavy equipment training programs that you can complete in as little as three weeks. Explore your options at our multiple locations across the country.