Portal cranes are widely used and classified, and the specific type is determined by the form and structure of the main beam. According to the number of main beams, it can be classified into single beam bridge and double beam bridge; According to the structure, it can be divided into box structure bridge, steel beam bridge, and precision frame bridge. The performance of each structural type is different. Box structure bridge is a widely used type with advantages such as simple process, easy assembly, strong applicability, good torsional stiffness, and automatic welding. However, it is heavy, easy to lower the main beam, poor horizontal stiffness, difficult to weld the connection weld between the belly plate and the upper wing, and has a low service life. At the same time, the welding between the transverse stiffening plate and the upper wing flange plate is prone to cracking. The main beam of the steel beam structure is generally made of I-beams, which are commonly used in small cars and have a simple structure with a small lifting capacity. With the application of new processes, new structures, and modern design methods, these shortcomings are gradually being improved. When designing the bridge structure of a bridge crane, several basic requirements must be met: the rigidity and strength of the bridge should be sufficient; The bridge should be well coordinated with the mechanism of the large and small vehicles to ensure normal operation; The reduction of the weight of the bridge structure contributes to economic significance, therefore, the design of the self weight structure should be minimized as much as possible to be aesthetically pleasing and facilitate mass production.