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In bridge construction, floating cranes of two main groups are used:
- special collapsible floating crane barge
- floating installations of land cranes (full-swing arrowheads, stiff-legged derricks, gantry) on inventory pontoons or on general purpose barges.
Floating cranes, including the largest barge crane in the world, are designed to:
- support the construction of mooring and coastal protection structures on the seas, rivers, and reservoirs
- for loading and unloading heavy cargoes from ships in ports and roads
- overloading of bulky cargoes
- on the completion of ships dropped from the stocks, as well as on the repair of vessels afloat.
In addition, largest floating crane can be used in the construction of bridge supports. However, the biggest floating crane in the world limits the area of their application to the lower reaches of large rivers flowing into the sea.
Modern universal largest floating crane are built full swing with a swinging boom, two hooks – main and auxiliary – for large and small loads, and equipped with grabs.
Navigation largest barge cranes operating in marine conditions are for the most part self-propelled, and cranes for river works are usually moved by tugboats. For movement on short distances during operation, largest barge crane in the world is equipped with driving spikes and mooring ends.
Universal cranes: biggest floating crane in the world
Universal floating cranes have found wide application in hydro technical construction due to the following advantages:
- significant load-carrying capacity (from 50 to 100 tons with cargo moments from 1,000 to 3,000 tons), which makes it possible to erect such structures with large elements weighing up to 100 tons
- quick transfer from the transport position to working and vice versa without mounting and dismantling of crane structures and mechanisms
- free movement afloat along the front of the object under construction, for which no temporary structures (overpasses, roads, etc.) are required
- a relatively small sediment (1.5-2.5 m), which makes it possible to build shore-protecting structures by floating cranes in the immediate vicinity of the shore.
Disadvantages of cranes
However, some disadvantages are inherent to these cranes, which primarily include:
- heavy weight (from 300 to 1,100 tons together with the vessel). Therefore, the weight characteristics (0.5-2.4) are much worse for floating cranes than for derrick cranes, and consequently, the higher the cost of a machine shift
- restriction of work during water excitement over 2-3 points and ice formation, because of which in open water areas the floating crane can work from a third to half of all the calendar time of the year
- large overall dimensions that do not allow the 50-100-ton floating cranes to be driven along inland waterways, including between the Black, Baltic and Caspian seas, which reduces maneuverability of the crane fleet
- restriction of the weight of prefabricated elements of river hydraulic structures up to 15 tons, since for their installation, it is possible to use only small cranes of capacity and dimensions that can pass under bridges and through locks on rivers and canals.
Universal floating cranes are built both self-propelled and non-self-propelled (collapsible and combined self-propelled cranes are not produced).