According to the main beam structure, gantry cranes can be divided into the following three categories:
1. Truss beam gantry crane
The structural form welded by angle steel or I-beam has the advantages of low cost, light weight, and good wind resistance. However, because of the large number of welding points and the defects of the trusses themselves, the truss beams also have the drawbacks of large deflection, low rigidity, relatively low reliability, and frequent detection of welding spots. Suitable for sites with low safety requirements and low lifting weight.
2. Box girder gantry crane
The use of steel plates welded into a box structure, with high safety, stiffness and other characteristics. It is generally used for gantry cranes with large tonnage and oversized tonnage. For example, the MGhz 1200 on the right shows a weight of 1200 tons. It is the largest gantry crane in China, and the main beam adopts a box girder structure. The box girder also has the disadvantages of high cost, heavy self, and poor wind resistance.
3. Honeycomb beam gantry crane
Generally refers to the "isosceles triangle honeycomb beam", the main beam end face is triangular, with honeycomb holes on both sides of the oblique belly, the upper and lower parts of the chord. The honeycomb beam absorbs the characteristics of the truss beam and the box girder. Compared with the truss girder, it has greater rigidity, less deflection, and higher reliability. However, due to the welding of steel plates, the self-weight and cost are slightly higher than those of trussed beams. Suitable for use in frequent or heavy lifting venues or beam yards. Since this type of beam is a patented product, there are fewer manufacturers.