Let's share some information about double girder gantry crane.

Double main girder gantry cranes have strong load-bearing capacity, large spans, good overall stability, and many varieties. However, compared with single main girder gantry cranes with the same lifting capacity, their own mass is larger and the cost is higher. According to the different main beam structures, it can be divided into two forms: box beam and truss. Generally, box-shaped structures are used.

According to the main beam structure

1. Truss beam

The structural form welded by angle steel or I-beam has the advantages of low cost, light weight and good wind resistance. However, due to the large number of welding points and the defects of the truss itself, the truss beam also has shortcomings such as large deflection, low stiffness, relatively low reliability, and the need for frequent detection of welding points. It is suitable for sites with lower safety requirements and smaller lifting capacity.

2. Box beam

Steel plates are welded into a box structure, which has the characteristics of high safety and high stiffness. Generally used for large-tonnage and ultra-large-tonnage gantry cranes. 

3. Honeycomb beam

Generally referred to as "isosceles triangle honeycomb beam", the end face of the main beam is triangular, there are honeycomb holes on the oblique webs on both sides, and there are chords on the upper and lower parts. Honeycomb beams absorb the characteristics of truss beams and box beams. Compared with truss beams, they have greater stiffness, smaller deflection, and higher reliability. However, due to the use of steel plate welding, the self-weight and cost are slightly higher than that of truss beams. It is suitable for sites or beam sites with frequent use or heavy lifting capacity. Since this beam type is a patented product, there are fewer manufacturers.

According to use form

1. Ordinary gantry crane

Orbital gantry crane

This kind of crane mostly adopts box type and truss type structure, and has the most wide range of uses. It can handle various finished items and bulk materials, with a lifting capacity of less than 100 tons and a span of 4 to 39 meters. Ordinary gantry cranes with grab buckets work at a higher level. Ordinary gantry cranes mainly refer to hook, grab, electromagnetic, and hoist gantry cranes, and also include semi-gantry cranes.

2. Hydro-power station gantry crane

It is mainly used for lifting, opening and closing gates, and can also be used for installation operations. The lifting capacity reaches 80 to 500 tons, the span is small, 8 to 16 meters, and the lifting speed is low, 1 to 5 meters/min. Although this kind of crane is not frequently lifted, the work is very heavy once it is used, so the work level must be appropriately increased.

3. Shipbuilding gantry crane

Used to assemble the hull on the slipway, there are always two lifting trolleys: one has two main hooks, running on the track on the upper flange of the bridge; the other has a main hook and an auxiliary hook, on the lower flange of the bridge. Run on rails to flip and lift large hull segments. The lifting capacity is generally 100 to 1500 tons; the span is up to 185 meters; the lifting speed is 2 to 15 meters/min, and there is a micro movement speed of 0.1 to 0.5 meters/min.

4. Container gantry crane

Used in container terminals. Trailer unloading containers from ship on quay wall container carrying bridge Rail gantry crane After being transported to the yard or rear, they are stacked by a container gantry crane or directly loaded onto a truck for transportation, which can speed up the turnover of container carrying bridges or other cranes. A yard that can stack containers with 3 to 4 layers in height and 6 rows in width is usually of tire type, but rail type is also used. Compared with container straddle trucks, container gantry cranes have larger spans and heights on both sides of the mast. In order to meet the transportation needs of port terminals, this kind of crane has a higher working level. The lifting speed is 8 to 10 meters/min; the span is determined by the number of rows of containers that need to be spanned, and the maximum is about 60 meters. The lifting weights of 20-foot, 30-foot, and 40-foot containers are respectively about 20 tons and 25 tons. and 30 tons.

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