Extremely large tower cranes are used in
the construction of today’s super tall skyscrapers such as the Wilshire Grand
Center in Los Angeles and the Salesforce Tower in San Francisco. Tower cranes assist with lifting heavy loads
of steel, concrete, generators and other building materials and can be erected
to grow taller as a construction project moves upward. The typical maximum unsupported height of a
tower crane is 265 ft. and the maximum reach of the jib is 230 ft. However a tower crane can grow right along
with the height of the skyscraper’s construction once it is secured to the
building. A tower crane’s maximum
lifting strength is generally around 19.8 tons.
Although there are different types of tower
cranes, for the most part, the components are the same. The mast is the main supporting tower of the
crane and is made from steel trussed sections.
The engine that allows the crane to rotate is called the slewing unit
and sits on top of the mast with the operating cabin and controls just above
that. The jib is the operating arm and
is the piece that extends horizontally from the mast. The two common types of jibs are the luffing
jib that moves up and down the crane and a fixed jib that is equipped with a
trolley to move materials horizontally.
The hook is used to connect materials to the crane, and large concrete
weights behind the mast are used to counteract the weight of the materials
being lifted by the hook.
A tower crane must be stabilized at the
jobsite before it is ready for use. This
involves constructing a concrete pad equipped with large anchor bolts embedded
into the concrete to secure the base of the crane. When the tower crane reaches its maximum
height, it can be tied to the side of the structure with steel collars and
moved upward to accommodate the upward needs of the project.
The Conco Companies’ mission is to be
the best supplier of concrete services in the Western United States and to
bring expertise and unsurpassed quality to each project. We continue to upgrade
and expand facilities to better serve the growing market for public works
projects, commercial, parking structures, educational, and other construction
development.
Sources:en.wikipedia.org/wiki/Crane_(machine),
science.howstuffworks.com/transport/engines-equipment/tower-crane.htm
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