Construction method of cantilever crane
Cantilever crane is a commonly used lifting equipment.In the cantilever crane,there are many construction methods,and we usually have cantilever assembly method and cantilever casting method.
In the cantilever crane,the cantilever assembly method uses the cantilever crane to lift the prefabricated beam segment to the installation position,and then uses epoxy resin glue and applies prestress to connect the prefabricated beam segment into a whole.The number of segments for cantilever assembly mainly depends on the lifting capacity of the cantilever crane,and the segment length is 2-5m.If the segment is too long,it will be heavy,requiring a large lifting capacity of the suspension assembly crane.If the segment is too short,there will be many assembly joints,and the construction period will also be extended.Because of the large sectional area of the cantilever root,the segment length is relatively short,and then gradually increases towards the end.
The assembly includes such processes as hoisting and positioning,epoxy adhesive bonding and tendon pulling and prestressing.Generally,it takes about 1-1.5 days to assemble a segment.
In addition,the cantilever assembly construction is adopted in the cantilever crane.The beam segment prefabrication can be carried out simultaneously with the bridge substructure construction,reducing the shrinkage and creep of the beam segment concrete,which is beneficial to the main beam alignment in the later stage of bridge completion.In addition,the cantilever assembly method is adopted for construction,and the beam segment is prefabricated at the site,which is easy to ensure the quality.However,the assembly adopts epoxy adhesive bonding,and the prestressed tendons are connected through the reserved holes.Compared with the cantilever casting method,the structural integrity is poor,and the construction deformation control is difficult,and the closure accuracy is often low.
Cantilever crane has little planning requirements for architects of pre designed houses.The cantilever crane(also known as the revolving column crane)installed on the ground does not rely on the superstructure of the house as a support,but only acts on its own foundation.On the contrary,the cantilever crane installed on the column is either supported on the column or against the column.Therefore,certain requirements for structural strength and stiffness are put forward.
The cantilever crane lifts the goods by the movement of the trolley along the lower flange of the cantilever rod and the movement of a chain hoist.The winch can be electric or manual.After lifting the goods,the cantilever rod rotates around the fixed column,and then the goods are lowered at the required place.The movement of the trolley and the rotation of the cantilever are often done manually.
The cantilever boom is 8 feet to 20 feet long,with a lifting capacity of 0.25 tons to 5 tons,and 0.5 tons to 1 tons are commonly used.
Common uses of boom cranes include mechanical service operations,assembly lines,air hammers,and unloading platforms.Sometimes,a combination of a pair of cantilever cranes,a monorail crane and a forklift is enough to transport goods from the unloading platform to a place where an overhead crane or a lifting crane can be used.The cheap cantilever crane can avoid the bridge crane from engaging in small work for a long time.
