Single cantilever gantry crane: This structural form is often chosen due to site limitations. 2、 Main beam structure 1. The truss beam is a structural form welded with angle steel or I-beam, which has the advantages of low cost, light weight, and good wind resistance. However, due to the large number of welding points and defects in the truss itself, the truss beam also has disadvantages such as large deflection, low stiffness, relatively low reliability, and the need for frequent detection of welding points. Suitable for venues with low safety requirements and small lifting capacity. 2. The box girder is welded with steel plates to form a box structure, which has the characteristics of high safety and high rigidity. Generally used for gantry cranes with large and super large tonnage. Box girders also have disadvantages such as high cost, heavy weight, and poor wind resistance. 3、 Main beam form 1. Single main beam single main beam gantry crane has a simple structure, easy manufacturing and installation, and small self weight. The main beam is mostly a skewed rail box frame structure. Compared with double girder gantry cranes, the overall stiffness is weaker. Therefore, when the lifting capacity Q is ≤ 50t and the span S is ≤ 35m, this form can be used. The single girder gantry crane has two types of gantry legs: L-shaped and C-shaped. L-shaped manufacturing and installation are convenient, with good stress conditions and relatively small self weight
However, the space for lifting goods through the support legs is relatively small. The C-shaped legs are designed to be inclined or curved, with the aim of providing ample lateral space for goods to pass smoothly through the legs. 2. The double main beam gantry crane has strong bearing capacity, large span, good overall stability, and many varieties. However, its own weight is larger than that of a single main beam gantry crane with the same lifting capacity, and the cost is also higher. According to the different structures of the main beam, it can be divided into two forms: box girder and truss. Box shaped structures are generally used.