Types of Construction Cranes
Mobile and Fixed
Cranes may be either mobile or fixed. Mobile cranes can move on their own, or are easily transported on a flatbed lorry. Some are built as part of a customized vehicle, similar to the ladder and bucket lorries used by fire fighters. There are several advantages to these lorry cranes; most can be driven on roads and highways without a police escort, which saves the contractor time and money.
Crawler Cranes
Larger mobile cranes may be known as crawlers (or crawler cranes). These can move around a construction site under their own power; they lack wheels, however, and are instead equipped with a series of tracks (or crawlers) similar to a military tank. Using the track system spreads the weight of the crane over a larger area and helps stabilize it, preventing tip-overs. Because they are so heavy and sturdy, crawler cranes are not driven on roads. When the crane is moved to a different construction site, it is broken down into pieces and re-assembled at its new home. Dismantling the crane and safely transporting each piece is an extremely expensive operation that may take days or weeks, depending on the distance covered.
Flanged Railroad Cranes
Railroad cranes may be used to load or unload shipping containers, move train cars and repair tracks; they may also be used to clean up the track after an accident. They don’t have traditional tires or tracks, but use flanged metal wheels to travel along the rail line. Cargo vessels may also be loaded and unloaded using sidelift cranes, which specialize in moving objects from side to side and generally have tires rather than flanged wheels.
Floating Cranes
Floating cranes are vital to shipbuilding, bridge and dam construction and in the oil/natural gas industry. Floating cranes are always large; the smallest sit on large pontoons and are useful for unloading cargo and repairing ports. Larger models are usually constructed on a specialized barge and have tremendous lifting capacity – often about 10,000 short tonnes. They’re effective for building or moving bridges, and are often used to salvage vessels and retrieve large portions of shipwrecks buried deep beneath the water’s surface.
Aerial Cranes: Helicopters and Dirigibles
One of the most unusual cranes is the aerial crane (or sky crane). These are modified helicopters and are essential in fighting wildfires because of the enormous amount of water that the bucket accommodates. This is far from their only application, however; aerial cranes are also used to install heavy equipment such as air conditioners and elevator motors on the roofs of tall buildings. More rarely, an aerial crane may transport trucks, cars or swimming pool liners. It’s interesting to note that although nearly all modern aerial cranes are helicopters, dirigibles may also be used for that purpose. However, most airship cranes designed after the Hindenburg disaster have never actually been built.
Citations:
- Photo by elbfoto
Article by Endeavour International who provide Crimping Machines for all aspects of Construction