Form and structure of main girder of gantry crane

1. Single girder for gantry crane

Gantry crane single girder gantry crane structure is simple, easy to manufacture and install, its own quality is small, the girder is mostly off-track box frame structure.

Compared with the double girder gantry crane, the overall stiffness is weaker.

Therefore, when the lifting weight Q is less than or equal to 50t and the span S is less than or equal to 35m, this form can be adopted.

Single girder gantry crane gantry leg has L - type and C - type two forms.

The manufacturing and installation of l-type is convenient, with good stress condition and low quality. However, the space for lifting goods through the leg is relatively small.

The leg of type C is inclined or bent so that there is more lateral space for goods to pass through the foot.

2. Double girder

Double girder gantry crane bearing capacity, span, overall stability, variety, but its own quality and the same weight of the single girder gantry crane is larger, higher cost.

According to the structure of the main beam, it can be divided into box beam and truss.

Generally, box-shaped girder structure is adopted

1. The truss beam

The structure formed by welding Angle steel or i-beam steel has the advantages of low cost, light weight and good wind resistance.

However, due to the many welding points and the defects of truss itself, truss beam also has the disadvantages of large deflection, small stiffness and relatively low reliability, requiring frequent detection of welding points.

Suitable for the site with low safety requirement and low lifting weight.

2. The box girder

Welded steel plate into a box structure, with high safety, stiffness and other characteristics.

Generally used for large tonnage and large tonnage gantry crane.

As shown in the figure on the right, MGhz1200, with a lifting weight of 1200 tons, is the largest gantry crane in China. The main girder adopts the box girder structure.

The box girder also has the disadvantages of high cost, self - weight and poor wind resistance.